

<!-- RR Donnelley Xcelerate Taxonomy Labels Linkbase, based on XBRL 2.1  http://www.rrdonnelley.com/ -->
<!-- Version: 6.22.4 -->
<!-- Round: 8 -->
<!-- Creation date: 2016-03-15T15:06:54Z -->
<!-- Copyright (c) 2005-2013 R.R. Donnelley & Sons Company All Rights Reserved. -->
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_CommitmentAndContingenciesTable_lbl" xml:lang="en-US" id="id_9891417_1874207_2_1">Commitment And Contingencies [Table]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_lbl" xml:lang="en-US" id="id_9891417_1640697_2_1">Commitments and Contingencies Disclosure [Abstract]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xml:lang="en-US" id="id_9891417_1641131_2_1">Commitments and Contingencies</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_CommitmentsAndContingenciesLineItems_lbl" xml:lang="en-US" id="id_9891417_1904563_3_1">Commitments And Contingencies [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_CommitmentsAndContingenciesLineItems_lbl" xml:lang="en-US" id="id_9891417_1904563_1_1">Commitments And Contingencies [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_CommitmentsAndContingenciesLineItems_lbl" xml:lang="en-US" id="id_9891417_1904563_2_1">Commitments And Contingencies [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_CommitmentsAndContingenciesLineItems" xlink:to="zfgn_CommitmentsAndContingenciesLineItems_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_CommitmentsAndContingenciesTable_lbl" xml:lang="en-US" id="id_9891417_1852432_3_1">Commitments And Contingencies [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_CommitmentsAndContingenciesTable_lbl" xml:lang="en-US" id="id_9891417_1852432_1_1">Commitments And Contingencies [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_CommitmentsAndContingenciesTable_lbl" xml:lang="en-US" id="id_9891417_1852432_2_1">Commitments And Contingencies [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_CommitmentsAndContingenciesTable" xlink:to="zfgn_CommitmentsAndContingenciesTable_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockMember_lbl" xml:lang="en-US" id="id_9891417_1632657_1_1">Common Stock [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockMember_lbl" xml:lang="en-US" id="id_9891417_1632657_2_1">Common Stock [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockMember" xlink:to="us-gaap_CommonStockMember_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xml:lang="en-US" id="id_9891417_1637092_1_1">Common Stock, Par or Stated Value Per Share</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xml:lang="en-US" id="id_9891417_1637092_2_1">Common stock, par value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xml:lang="en-US" id="id_9891417_1637092_12_1">Common stock, par value per share</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockParOrStatedValuePerShare" xlink:to="us-gaap_CommonStockParOrStatedValuePerShare_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xml:lang="en-US" id="id_9891417_1633455_1_1">Common Stock, Shares Authorized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xml:lang="en-US" id="id_9891417_1633455_2_1">Common stock, shares authorized</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockValue_lbl" xml:lang="en-US" id="id_9891417_1646846_2_1">Common stock, $0.001 par value per share; 115,000,000 shares authorized at December 31, 2015 and 2014; 27,242,503 and 22,879,160 shares issued and outstanding at December 31, 2015 and 2014, respectively</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskCreditRisk" xlink:label="us-gaap_ConcentrationRiskCreditRisk"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskCreditRisk_lbl" xml:lang="en-US" id="id_9891417_1636695_1_1">Concentration Risk, Credit Risk, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConcentrationRiskCreditRisk_lbl" xml:lang="en-US" id="id_9891417_1636695_2_1">Concentration of Credit Risk and of Significant Suppliers</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskCreditRisk" xlink:to="us-gaap_ConcentrationRiskCreditRisk_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_ConsultantMember" xlink:label="zfgn_ConsultantMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_ConsultantMember_lbl" xml:lang="en-US" id="id_9891417_1935455_3_1">Consultant [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_ConsultantMember_lbl" xml:lang="en-US" id="id_9891417_1935455_1_1">Consultant [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_ConsultantMember_lbl" xml:lang="en-US" id="id_9891417_1935455_2_1">Consultant [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_ConsultantMember" xlink:to="zfgn_ConsultantMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_ConversionOfLiabilitiesToCommonStockAmountConverted" xlink:label="zfgn_ConversionOfLiabilitiesToCommonStockAmountConverted"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_ConversionOfLiabilitiesToCommonStockAmountConverted_lbl" xml:lang="en-US" id="id_9891417_1826902_3_1">The value of milestone liabilities that were converted to common stock during the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_ConversionOfLiabilitiesToCommonStockAmountConverted_lbl" xml:lang="en-US" id="id_9891417_1826902_1_1">Conversion Of Liabilities To Common Stock, Amount Converted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_ConversionOfLiabilitiesToCommonStockAmountConverted_lbl" xml:lang="en-US" id="id_9891417_1826902_2_1">Conversion of milestone liabilities to common stock</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_ConversionOfLiabilitiesToCommonStockAmountConverted" xlink:to="zfgn_ConversionOfLiabilitiesToCommonStockAmountConverted_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConversionOfStockAmountConverted1" xlink:label="us-gaap_ConversionOfStockAmountConverted1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConversionOfStockAmountConverted1_lbl" xml:lang="en-US" id="id_9891417_1650519_1_1">Conversion of Stock, Amount Converted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConversionOfStockAmountConverted1_lbl" xml:lang="en-US" id="id_9891417_1650519_2_1">Conversion of redeemable preferred stock to common stock</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConversionOfStockAmountConverted1" xlink:to="us-gaap_ConversionOfStockAmountConverted1_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion" xlink:label="us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion_lbl" xml:lang="en-US" id="id_9891417_1632257_1_1">Convertible Preferred Stock, Shares Issued upon Conversion</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion_lbl" xml:lang="en-US" id="id_9891417_1632257_2_1">Redeemable convertible preferred stock converted into common stock shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion" xlink:to="us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CorporateBondSecuritiesMember" xlink:label="us-gaap_CorporateBondSecuritiesMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CorporateBondSecuritiesMember_lbl" xml:lang="en-US" id="id_9891417_1635118_1_1">Corporate Bond Securities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CorporateBondSecuritiesMember_lbl" xml:lang="en-US" id="id_9891417_1635118_2_1">Corporate Bonds [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CorporateBondSecuritiesMember" xlink:to="us-gaap_CorporateBondSecuritiesMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_CorporateDebtSecuritiesDueAfterOneYearThroughTwoYearsMember" xlink:label="zfgn_CorporateDebtSecuritiesDueAfterOneYearThroughTwoYearsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_CorporateDebtSecuritiesDueAfterOneYearThroughTwoYearsMember_lbl" xml:lang="en-US" id="id_9891417_1832727_3_1">Corporate Debt Securities Due After One Year Through Two Years [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_CorporateDebtSecuritiesDueAfterOneYearThroughTwoYearsMember_lbl" xml:lang="en-US" id="id_9891417_1832727_1_1">Corporate Debt Securities Due After One Year Through Two Years [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_CorporateDebtSecuritiesDueAfterOneYearThroughTwoYearsMember_lbl" xml:lang="en-US" id="id_9891417_1832727_2_1">Corporate Bonds (Due After 1 Year Through 2 Years) [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_CorporateDebtSecuritiesDueAfterOneYearThroughTwoYearsMember" xlink:to="zfgn_CorporateDebtSecuritiesDueAfterOneYearThroughTwoYearsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_CorporateDebtSecuritiesDueWithinOneYearMember" xlink:label="zfgn_CorporateDebtSecuritiesDueWithinOneYearMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_CorporateDebtSecuritiesDueWithinOneYearMember_lbl" xml:lang="en-US" id="id_9891417_1841780_3_1">Corporate Debt Securities Due Within One Year [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_CorporateDebtSecuritiesDueWithinOneYearMember_lbl" xml:lang="en-US" id="id_9891417_1841780_1_1">Corporate Debt Securities Due Within One Year [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_CorporateDebtSecuritiesDueWithinOneYearMember_lbl" xml:lang="en-US" id="id_9891417_1841780_2_1">Corporate Bonds (Due within 1 Year) [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_CorporateDebtSecuritiesDueWithinOneYearMember" xlink:to="zfgn_CorporateDebtSecuritiesDueWithinOneYearMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="us-gaap_CreditFacilityAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CreditFacilityAxis_lbl" xml:lang="en-US" id="id_9891417_1633091_1_1">Credit Facility [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CreditFacilityAxis_lbl" xml:lang="en-US" id="id_9891417_1633091_2_1">Credit Facility [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="us-gaap_CreditFacilityDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CreditFacilityDomain_lbl" xml:lang="en-US" id="id_9891417_1633092_1_1">Credit Facility [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CreditFacilityDomain_lbl" xml:lang="en-US" id="id_9891417_1633092_2_1">Credit Facility [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_CreditFacilityDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_CreditFacilityMember" xlink:label="zfgn_CreditFacilityMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_CreditFacilityMember_lbl" xml:lang="en-US" id="id_9891417_1745947_3_1">Credit Facility [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_CreditFacilityMember_lbl" xml:lang="en-US" id="id_9891417_1745947_1_1">Credit Facility [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_CreditFacilityMember_lbl" xml:lang="en-US" id="id_9891417_1745947_2_1">Credit Facility [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_CreditFacilityMember" xlink:to="zfgn_CreditFacilityMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="dei_CurrentFiscalYearEndDate"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xml:lang="en-US" id="id_9891417_1638733_1_1">Current Fiscal Year End Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xml:lang="en-US" id="id_9891417_1638733_2_1">Current Fiscal Year End Date</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CurrentFiscalYearEndDate" xlink:to="dei_CurrentFiscalYearEndDate_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtDisclosureAbstract" xlink:label="us-gaap_DebtDisclosureAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtDisclosureAbstract_lbl" xml:lang="en-US" id="id_9891417_1640266_1_1">Debt Disclosure [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtDisclosureAbstract_lbl" xml:lang="en-US" id="id_9891417_1640266_2_1">Debt Disclosure [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtDisclosureAbstract" xlink:to="us-gaap_DebtDisclosureAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtDisclosureTextBlock" xlink:label="us-gaap_DebtDisclosureTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtDisclosureTextBlock_lbl" xml:lang="en-US" id="id_9891417_1633888_1_1">Debt Disclosure [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtDisclosureTextBlock_lbl" xml:lang="en-US" id="id_9891417_1633888_2_1">Notes Payable</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtDisclosureTextBlock" xlink:to="us-gaap_DebtDisclosureTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_DebtDiscountAndFinanceCostsMember" xlink:label="zfgn_DebtDiscountAndFinanceCostsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_DebtDiscountAndFinanceCostsMember_lbl" xml:lang="en-US" id="id_9891417_1705876_3_1">Debt Discount And Finance Costs [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_DebtDiscountAndFinanceCostsMember_lbl" xml:lang="en-US" id="id_9891417_1705876_1_1">Debt Discount And Finance Costs [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_DebtDiscountAndFinanceCostsMember_lbl" xml:lang="en-US" id="id_9891417_1705876_2_1">Debt Discount and Finance Costs [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_DebtDiscountAndFinanceCostsMember" xlink:to="zfgn_DebtDiscountAndFinanceCostsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="us-gaap_DebtInstrumentAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xml:lang="en-US" id="id_9891417_1631478_1_1">Debt Instrument [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xml:lang="en-US" id="id_9891417_1631478_2_1">Debt Instrument [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_DebtInstrumentFairValueCarryingValueAbstract" xlink:label="zfgn_DebtInstrumentFairValueCarryingValueAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_DebtInstrumentFairValueCarryingValueAbstract_lbl" xml:lang="en-US" id="id_9891417_1659456_3_1">Debt Instrument Fair Value Carrying Value [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_DebtInstrumentFairValueCarryingValueAbstract_lbl" xml:lang="en-US" id="id_9891417_1659456_1_1">Debt Instrument Fair Value Carrying Value [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_DebtInstrumentFairValueCarryingValueAbstract_lbl" xml:lang="en-US" id="id_9891417_1659456_2_1">Debt Instrument Fair Value Carrying Value [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_DebtInstrumentFairValueCarryingValueAbstract" xlink:to="zfgn_DebtInstrumentFairValueCarryingValueAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentIncreaseAccruedInterest" xlink:label="us-gaap_DebtInstrumentIncreaseAccruedInterest"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentIncreaseAccruedInterest_lbl" xml:lang="en-US" id="id_9891417_1644926_1_1">Debt Instrument, Increase, Accrued Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentIncreaseAccruedInterest_lbl" xml:lang="en-US" id="id_9891417_1644926_2_1">Charges to interest expense of debt outstanding</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentIncreaseAccruedInterest" xlink:to="us-gaap_DebtInstrumentIncreaseAccruedInterest_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage_lbl" xml:lang="en-US" id="id_9891417_1631481_1_1">Debt Instrument, Interest Rate, Effective Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage_lbl" xml:lang="en-US" id="id_9891417_1631481_2_1">Effective annual interest rate</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:to="us-gaap_DebtInstrumentInterestRateEffectivePercentage_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="us-gaap_DebtInstrumentLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xml:lang="en-US" id="id_9891417_1639119_1_1">Debt Instrument [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xml:lang="en-US" id="id_9891417_1639119_2_1">Debt Instrument [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xml:lang="en-US" id="id_9891417_1632266_1_1">Debt Instrument, Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xml:lang="en-US" id="id_9891417_1632266_2_1">Debt Instrument, Name [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="us-gaap_DebtInstrumentNameDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid" xlink:label="us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid_lbl" xml:lang="en-US" id="id_9891417_1645008_1_1">Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_DeferredTaxAssetsGrossChangeInAmount_lbl" xml:lang="en-US" id="id_9891417_2017332_3_1">Amount of overstatement (understatement) of gross deferred tax assets.</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment_lbl" xml:lang="en-US" id="id_9891417_1651918_2_1">Capitalized research and development expenses</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment" xlink:to="us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredTaxAssetsNetCurrent_lbl" xml:lang="en-US" id="id_9891417_1651676_1_1">Deferred Tax Assets, Net of Valuation Allowance, Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_DeferredTaxAssetsNetCurrent_lbl" xml:lang="en-US" id="id_9891417_1651676_6_1">Total current deferred tax assets</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredTaxAssetsNetCurrentClassificationAbstract_lbl" xml:lang="en-US" id="id_9891417_1642816_1_1">Deferred Tax Assets, Net of Valuation Allowance, Current Classification [Abstract]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_DeferredTaxAssetsNetNoncurrent_lbl" xml:lang="en-US" id="id_9891417_1651169_6_1">Total noncurrent deferred tax assets</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_lbl" xml:lang="en-US" id="id_9891417_1648153_1_1">Deferred Tax Assets, Operating Loss Carryforwards</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_lbl" xml:lang="en-US" id="id_9891417_1648153_2_1">Net operating loss carryforwards</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic_lbl" xml:lang="en-US" id="id_9891417_1650784_1_1">Deferred Tax Assets, Operating Loss Carryforwards, Domestic</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic_lbl" xml:lang="en-US" id="id_9891417_1650784_2_1">Operating loss carryforwards, federal</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwards" xlink:label="us-gaap_DeferredTaxAssetsTaxCreditCarryforwards"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredTaxAssetsTaxCreditCarryforwards_lbl" xml:lang="en-US" id="id_9891417_1651677_2_1">Tax credit carryforwards</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_DenominatorAbstract_lbl" xml:lang="en-US" id="id_9891417_1789733_3_1">Denominator [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_DenominatorAbstract_lbl" xml:lang="en-US" id="id_9891417_1789733_1_1">Denominator [Abstract]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_DepositsForLeasedProperty_lbl" xml:lang="en-US" id="id_9891417_1977391_3_1">The amount of cash paid for deposits on leased property.</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_DevelopmentBasedMilestonesMember_lbl" xml:lang="en-US" id="id_9891417_1878711_3_1">Development Based Milestones [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_DevelopmentBasedMilestonesMember_lbl" xml:lang="en-US" id="id_9891417_1878711_1_1">Development Based Milestones [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_DocumentAndEntityInformationAbstract_lbl" xml:lang="en-US" id="id_9891417_1666892_1_1">Document And Entity Information [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_DocumentAndEntityInformationAbstract_lbl" xml:lang="en-US" id="id_9891417_1666892_2_1">Document And Entity Information [Abstract]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_EffectiveIncomeTaxRateReconciliationOrphanDrugTaxCredits_lbl" xml:lang="en-US" id="id_9891417_2013131_3_1">Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to orphan drug tax credit.</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReceivable" xlink:to="us-gaap_IncomeTaxReceivable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable_lbl" xml:lang="en-US" id="id_9891417_1651075_1_1">Increase (Decrease) in Accounts Payable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable_lbl" xml:lang="en-US" id="id_9891417_1651075_2_1">Accounts payable</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInAccountsPayable" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities_lbl" xml:lang="en-US" id="id_9891417_1649795_1_1">Increase (Decrease) in Accrued Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities_lbl" xml:lang="en-US" id="id_9891417_1649795_2_1">Accrued expenses</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:to="us-gaap_IncreaseDecreaseInAccruedLiabilities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xml:lang="en-US" id="id_9891417_1631969_1_1">Increase (Decrease) in Operating Capital [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xml:lang="en-US" id="id_9891417_1631969_2_1">Changes in operating assets and liabilities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_lbl" xml:lang="en-US" id="id_9891417_1645210_1_1">Increase (Decrease) in Prepaid Expense and Other Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_lbl" xml:lang="en-US" id="id_9891417_1645210_14_1">Prepaid expenses and other current assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:to="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_IncreaseDecreaseInTaxIncentivesReceivable" xlink:label="zfgn_IncreaseDecreaseInTaxIncentivesReceivable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_IncreaseDecreaseInTaxIncentivesReceivable_lbl" xml:lang="en-US" id="id_9891417_1822475_3_1">The increase (decrease) during the reporting period in tax incentive receivable, which represents the amount due from tax authorities for refunds of overpayments or recoveries of taxes paid.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_IncreaseDecreaseInTaxIncentivesReceivable_lbl" xml:lang="en-US" id="id_9891417_1822475_1_1">Increase Decrease In Tax Incentives Receivable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="zfgn_IncreaseDecreaseInTaxIncentivesReceivable_lbl" xml:lang="en-US" id="id_9891417_1822475_14_1">Tax incentive receivable</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_IncreaseDecreaseInTaxIncentivesReceivable" xlink:to="zfgn_IncreaseDecreaseInTaxIncentivesReceivable_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_InitialPublicOfferingCost" xlink:label="zfgn_InitialPublicOfferingCost"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_InitialPublicOfferingCost_lbl" xml:lang="en-US" id="id_9891417_1763574_3_1">Initial Public Offering Cost</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_InitialPublicOfferingCost_lbl" xml:lang="en-US" id="id_9891417_1763574_1_1">Initial Public Offering Cost</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_InitialPublicOfferingCost_lbl" xml:lang="en-US" id="id_9891417_1763574_2_1">Offering costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_InitialPublicOfferingCost" xlink:to="zfgn_InitialPublicOfferingCost_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IntangibleAssetsFiniteLivedPolicy" xlink:label="us-gaap_IntangibleAssetsFiniteLivedPolicy"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IntangibleAssetsFiniteLivedPolicy_lbl" xml:lang="en-US" id="id_9891417_1638422_1_1">Intangible Assets, Finite-Lived, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IntangibleAssetsFiniteLivedPolicy_lbl" xml:lang="en-US" id="id_9891417_1638422_2_1">Patent Costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IntangibleAssetsFiniteLivedPolicy" xlink:to="us-gaap_IntangibleAssetsFiniteLivedPolicy_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestExpense" xlink:label="us-gaap_InterestExpense"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestExpense_lbl" xml:lang="en-US" id="id_9891417_1649043_1_1">Interest Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestExpense_lbl" xml:lang="en-US" id="id_9891417_1649043_2_1">Interest expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_InterestExpense_lbl" xml:lang="en-US" id="id_9891417_1649043_14_1">Interest expense</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestExpense" xlink:to="us-gaap_InterestExpense_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestPaid" xlink:label="us-gaap_InterestPaid"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestPaid_lbl" xml:lang="en-US" id="id_9891417_1644975_1_1">Interest Paid</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestPaid_lbl" xml:lang="en-US" id="id_9891417_1644975_2_1">Cash paid for interest</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestPaid" xlink:to="us-gaap_InterestPaid_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InvestmentIncomeAmortizationOfPremium" xlink:label="us-gaap_InvestmentIncomeAmortizationOfPremium"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InvestmentIncomeAmortizationOfPremium_lbl" xml:lang="en-US" id="id_9891417_1648426_1_1">Investment Income, Amortization of Premium</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InvestmentIncomeAmortizationOfPremium_lbl" xml:lang="en-US" id="id_9891417_1648426_2_1">Amortization of premium on marketable securities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentIncomeAmortizationOfPremium" xlink:to="us-gaap_InvestmentIncomeAmortizationOfPremium_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InvestmentIncomeNet" xlink:label="us-gaap_InvestmentIncomeNet"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InvestmentIncomeNet_lbl" xml:lang="en-US" id="id_9891417_1646240_1_1">Investment Income, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InvestmentIncomeNet_lbl" xml:lang="en-US" id="id_9891417_1646240_2_1">Interest income</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentIncomeNet" xlink:to="us-gaap_InvestmentIncomeNet_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="us-gaap_InvestmentTypeAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InvestmentTypeAxis_lbl" xml:lang="en-US" id="id_9891417_1643713_1_1">Investment Type [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InvestmentTypeAxis_lbl" xml:lang="en-US" id="id_9891417_1643713_2_1">Investment Type [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentTypeAxis" xlink:to="us-gaap_InvestmentTypeAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="us-gaap_InvestmentTypeCategorizationMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InvestmentTypeCategorizationMember_lbl" xml:lang="en-US" id="id_9891417_1635220_1_1">Investments [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InvestmentTypeCategorizationMember_lbl" xml:lang="en-US" id="id_9891417_1635220_2_1">Investments [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentTypeCategorizationMember" xlink:to="us-gaap_InvestmentTypeCategorizationMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IPOMember" xlink:label="us-gaap_IPOMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IPOMember_lbl" xml:lang="en-US" id="id_9891417_1634411_1_1">IPO [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IPOMember_lbl" xml:lang="en-US" id="id_9891417_1634411_2_1">IPO [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IPOMember" xlink:to="us-gaap_IPOMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" xlink:label="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims_lbl" xml:lang="en-US" id="id_9891417_1650553_1_1">Issuance of Stock and Warrants for Services or Claims</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims_lbl" xml:lang="en-US" id="id_9891417_1650553_2_1">Common stock issued in lieu of milestone payment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims_lbl" xml:lang="en-US" id="id_9891417_1650553_12_1">Issuance of common stock in lieu of milestone payment</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" xlink:to="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LeaseArrangementTypeAxis" xlink:label="us-gaap_LeaseArrangementTypeAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LeaseArrangementTypeAxis_lbl" xml:lang="en-US" id="id_9891417_1639226_1_1">Lease Arrangement, Type [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LeaseArrangementTypeAxis_lbl" xml:lang="en-US" id="id_9891417_1639226_2_1">Lease Arrangement, Type [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseArrangementTypeAxis" xlink:to="us-gaap_LeaseArrangementTypeAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LeaseArrangementTypeDomain" xlink:label="us-gaap_LeaseArrangementTypeDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LeaseArrangementTypeDomain_lbl" xml:lang="en-US" id="id_9891417_1640396_1_1">Lease Arrangement, Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LeaseArrangementTypeDomain_lbl" xml:lang="en-US" id="id_9891417_1640396_2_1">Lease Arrangement, Type [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseArrangementTypeDomain" xlink:to="us-gaap_LeaseArrangementTypeDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LeaseExpirationDate1" xlink:label="us-gaap_LeaseExpirationDate1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LeaseExpirationDate1_lbl" xml:lang="en-US" id="id_9891417_1644113_1_1">Lease Expiration Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LeaseExpirationDate1_lbl" xml:lang="en-US" id="id_9891417_1644113_2_1">Lease expiration date</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseExpirationDate1" xlink:to="us-gaap_LeaseExpirationDate1_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="us-gaap_LeaseholdImprovementsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xml:lang="en-US" id="id_9891417_1642130_1_1">Leasehold Improvements [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xml:lang="en-US" id="id_9891417_1642130_2_1">Leasehold Improvements [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseholdImprovementsMember" xlink:to="us-gaap_LeaseholdImprovementsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm" xlink:label="us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm_lbl" xml:lang="en-US" id="id_9891417_1638441_1_1">Lessee Leasing Arrangements, Operating Leases, Renewal Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm_lbl" xml:lang="en-US" id="id_9891417_1638441_2_1">Lease extension period</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm" xlink:to="us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Liabilities_lbl" xml:lang="en-US" id="id_9891417_1646694_1_1">Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_Liabilities_lbl" xml:lang="en-US" id="id_9891417_1646694_6_1">Total liabilities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_Liabilities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xml:lang="en-US" id="id_9891417_1646695_1_1">Liabilities and Equity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xml:lang="en-US" id="id_9891417_1646695_6_1">Total liabilities and stockholders' equity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xml:lang="en-US" id="id_9891417_1636826_1_1">Liabilities and Equity [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xml:lang="en-US" id="id_9891417_1636826_2_1">Liabilities and Stockholders' Equity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xml:lang="en-US" id="id_9891417_1647463_1_1">Liabilities, Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xml:lang="en-US" id="id_9891417_1647463_6_1">Total current liabilities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_LiabilitiesCurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="us-gaap_LiabilitiesCurrentAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xml:lang="en-US" id="id_9891417_1639229_1_1">Liabilities, Current [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xml:lang="en-US" id="id_9891417_1639229_2_1">Current liabilities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_LiabilitiesCurrentAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilityForUncertainTaxPositionsCurrent" xlink:label="us-gaap_LiabilityForUncertainTaxPositionsCurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilityForUncertainTaxPositionsCurrent_lbl" xml:lang="en-US" id="id_9891417_1646905_1_1">Liability for Uncertain Tax Positions, Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LiabilityForUncertainTaxPositionsCurrent_lbl" xml:lang="en-US" id="id_9891417_1646905_2_1">Uncertain tax position</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilityForUncertainTaxPositionsCurrent" xlink:to="us-gaap_LiabilityForUncertainTaxPositionsCurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_LicenseAgreementsMember" xlink:label="zfgn_LicenseAgreementsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_LicenseAgreementsMember_lbl" xml:lang="en-US" id="id_9891417_1663815_3_1">License Agreements [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_LicenseAgreementsMember_lbl" xml:lang="en-US" id="id_9891417_1663815_1_1">License Agreements [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_LicenseAgreementsMember_lbl" xml:lang="en-US" id="id_9891417_1663815_2_1">License Agreements [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_LicenseAgreementsMember" xlink:to="zfgn_LicenseAgreementsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_LicensingFeesPerProductMaximum" xlink:label="zfgn_LicensingFeesPerProductMaximum"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_LicensingFeesPerProductMaximum_lbl" xml:lang="en-US" id="id_9891417_1673817_3_1">Maximum fee the Company is obligated to pay per licensed product.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_LicensingFeesPerProductMaximum_lbl" xml:lang="en-US" id="id_9891417_1673817_1_1">Licensing Fees Per Product Maximum</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_LicensingFeesPerProductMaximum_lbl" xml:lang="en-US" id="id_9891417_1673817_2_1">Licensing fees per product maximum</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_LicensingFeesPerProductMaximum" xlink:to="zfgn_LicensingFeesPerProductMaximum_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_LikelihoodPercentageMinimum" xlink:label="zfgn_LikelihoodPercentageMinimum"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_LikelihoodPercentageMinimum_lbl" xml:lang="en-US" id="id_9891417_1790808_3_1">The minimum likelihood percentage threshold used to determine the amount of tax benefit to be recognized.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_LikelihoodPercentageMinimum_lbl" xml:lang="en-US" id="id_9891417_1790808_1_1">Likelihood Percentage Minimum</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_LikelihoodPercentageMinimum_lbl" xml:lang="en-US" id="id_9891417_1790808_2_1">Percentage of likelihood to be realized upon ultimate settlement, description</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_LikelihoodPercentageMinimum" xlink:to="zfgn_LikelihoodPercentageMinimum_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_LineOfCreditFacilityAdditionalFeePercentage" xlink:label="zfgn_LineOfCreditFacilityAdditionalFeePercentage"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_LineOfCreditFacilityAdditionalFeePercentage_lbl" xml:lang="en-US" id="id_9891417_1690428_3_1">The additional fee charged, as a percentage, on any amounts drawn under the Credit Facility.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_LineOfCreditFacilityAdditionalFeePercentage_lbl" xml:lang="en-US" id="id_9891417_1690428_1_1">Line Of Credit Facility Additional Fee Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_LineOfCreditFacilityAdditionalFeePercentage_lbl" xml:lang="en-US" id="id_9891417_1690428_2_1">Line of credit facility additional fee percentage</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_LineOfCreditFacilityAdditionalFeePercentage" xlink:to="zfgn_LineOfCreditFacilityAdditionalFeePercentage_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_lbl" xml:lang="en-US" id="id_9891417_1646682_1_1">Line of Credit Facility, Current Borrowing Capacity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_lbl" xml:lang="en-US" id="id_9891417_1646682_2_1">Current line of credit</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_LineOfCreditFacilityDebtDefaultMinimumAmount" xlink:label="zfgn_LineOfCreditFacilityDebtDefaultMinimumAmount"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_LineOfCreditFacilityDebtDefaultMinimumAmount_lbl" xml:lang="en-US" id="id_9891417_1669772_3_1">The minimum default amount over which the lender may exercise remedies against the Company.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_LineOfCreditFacilityDebtDefaultMinimumAmount_lbl" xml:lang="en-US" id="id_9891417_1669772_1_1">Line Of Credit Facility Debt Default Minimum Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_LineOfCreditFacilityDebtDefaultMinimumAmount_lbl" xml:lang="en-US" id="id_9891417_1669772_2_1">Credit facility default amount</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_LineOfCreditFacilityDebtDefaultMinimumAmount" xlink:to="zfgn_LineOfCreditFacilityDebtDefaultMinimumAmount_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityDescription" xlink:label="us-gaap_LineOfCreditFacilityDescription"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityDescription_lbl" xml:lang="en-US" id="id_9891417_1631996_1_1">Line of Credit Facility, Description</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityDescription_lbl" xml:lang="en-US" id="id_9891417_1631996_2_1">Line of credit facility description</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityDescription" xlink:to="us-gaap_LineOfCreditFacilityDescription_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityExpirationDate1" xlink:label="us-gaap_LineOfCreditFacilityExpirationDate1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityExpirationDate1_lbl" xml:lang="en-US" id="id_9891417_1638843_1_1">Line of Credit Facility, Expiration Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityExpirationDate1_lbl" xml:lang="en-US" id="id_9891417_1638843_2_1">Credit facility maturity date</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityExpirationDate1" xlink:to="us-gaap_LineOfCreditFacilityExpirationDate1_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityInitiationDate1" xlink:label="us-gaap_LineOfCreditFacilityInitiationDate1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityInitiationDate1_lbl" xml:lang="en-US" id="id_9891417_1637618_1_1">Line of Credit Facility, Initiation Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityInitiationDate1_lbl" xml:lang="en-US" id="id_9891417_1637618_2_1">Credit facility initiation date</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityInitiationDate1" xlink:to="us-gaap_LineOfCreditFacilityInitiationDate1_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityInterestRateDuringPeriod" xlink:label="us-gaap_LineOfCreditFacilityInterestRateDuringPeriod"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_lbl" xml:lang="en-US" id="id_9891417_1639607_1_1">Line of Credit Facility, Interest Rate During Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_lbl" xml:lang="en-US" id="id_9891417_1639607_2_1">Line of credit facility annual interest rate</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityInterestRateDuringPeriod" xlink:to="us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="us-gaap_LineOfCreditFacilityLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityLineItems_lbl" xml:lang="en-US" id="id_9891417_1641677_1_1">Line of Credit Facility [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityLineItems_lbl" xml:lang="en-US" id="id_9891417_1641677_2_1">Line of Credit Facility [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_LineOfCreditFacilityLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xml:lang="en-US" id="id_9891417_1645437_1_1">Line of Credit Facility, Maximum Borrowing Capacity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xml:lang="en-US" id="id_9891417_1645437_2_1">Maximum line of credit</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityPeriodicPaymentInterest" xlink:label="us-gaap_LineOfCreditFacilityPeriodicPaymentInterest"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityPeriodicPaymentInterest_lbl" xml:lang="en-US" id="id_9891417_1650456_1_1">Line of Credit Facility, Periodic Payment, Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityPeriodicPaymentInterest_lbl" xml:lang="en-US" id="id_9891417_1650456_2_1">Interest expense on credit facility</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityPeriodicPaymentInterest" xlink:to="us-gaap_LineOfCreditFacilityPeriodicPaymentInterest_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_lbl" xml:lang="en-US" id="id_9891417_1644771_1_1">Line of Credit Facility, Remaining Borrowing Capacity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_lbl" xml:lang="en-US" id="id_9891417_1644771_2_1">Additional line of credit</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="us-gaap_LineOfCreditFacilityTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityTable_lbl" xml:lang="en-US" id="id_9891417_1632384_1_1">Line of Credit Facility [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityTable_lbl" xml:lang="en-US" id="id_9891417_1632384_2_1">Line of Credit Facility [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityTable" xlink:to="us-gaap_LineOfCreditFacilityTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebt" xlink:label="us-gaap_LongTermDebt"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermDebt_lbl" xml:lang="en-US" id="id_9891417_1645693_1_1">Long-term Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LongTermDebt_lbl" xml:lang="en-US" id="id_9891417_1645693_6_1">Total</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_LongTermDebt_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xml:lang="en-US" id="id_9891417_1644415_1_1">Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xml:lang="en-US" id="id_9891417_1644415_2_1">2016</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:to="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermNotesPayable_lbl" xml:lang="en-US" id="id_9891417_1644883_1_1">Notes Payable, Noncurrent</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_lbl" xml:lang="en-US" id="id_9891417_1632391_1_1">Category of Item Purchased [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_lbl" xml:lang="en-US" id="id_9891417_1632391_2_1">Category of Item Purchased [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" xlink:to="us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_lbl" xml:lang="en-US" id="id_9891417_1636434_1_1">Long-term Purchase Commitment, Category of Item Purchased [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_lbl" xml:lang="en-US" id="id_9891417_1636434_2_1">Long-term Purchase Commitment, Category of Item Purchased [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:to="us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_lbl" xml:lang="en-US" id="id_9891417_1636044_1_1">Major Types of Debt and Equity Securities [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_lbl" xml:lang="en-US" id="id_9891417_1636044_2_1">Major Types of Debt and Equity Securities [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:to="us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_lbl" xml:lang="en-US" id="id_9891417_1634840_1_1">Major Types of Debt and Equity Securities [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_lbl" xml:lang="en-US" id="id_9891417_1634840_2_1">Major Types of Debt and Equity Securities [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:to="us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MarketableSecuritiesPolicy" xlink:label="us-gaap_MarketableSecuritiesPolicy"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MarketableSecuritiesPolicy_lbl" xml:lang="en-US" id="id_9891417_1637629_1_1">Marketable Securities, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MarketableSecuritiesPolicy_lbl" xml:lang="en-US" id="id_9891417_1637629_2_1">Marketable securities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MarketableSecuritiesPolicy" xlink:to="us-gaap_MarketableSecuritiesPolicy_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MarketableSecuritiesUnrealizedGainLoss" xlink:label="us-gaap_MarketableSecuritiesUnrealizedGainLoss"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MarketableSecuritiesUnrealizedGainLoss_lbl" xml:lang="en-US" id="id_9891417_1644636_1_1">Marketable Securities, Unrealized Gain (Loss)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MarketableSecuritiesUnrealizedGainLoss_lbl" xml:lang="en-US" id="id_9891417_1644636_2_1">Unrealized loss on marketable securities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MarketableSecuritiesUnrealizedGainLoss" xlink:to="us-gaap_MarketableSecuritiesUnrealizedGainLoss_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MaximumMember" xlink:label="us-gaap_MaximumMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MaximumMember_lbl" xml:lang="en-US" id="id_9891417_1633605_1_1">Maximum [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MaximumMember_lbl" xml:lang="en-US" id="id_9891417_1633605_2_1">Maximum [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MaximumMember" xlink:to="us-gaap_MaximumMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_MilestoneLiability" xlink:label="zfgn_MilestoneLiability"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_MilestoneLiability_lbl" xml:lang="en-US" id="id_9891417_1761571_3_1">Amount of payment due for milestones that have been achieved</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_MilestoneLiability_lbl" xml:lang="en-US" id="id_9891417_1761571_1_1">Milestone Liability</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_MilestoneLiability_lbl" xml:lang="en-US" id="id_9891417_1761571_2_1">Milestone payments due</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_MilestoneLiability" xlink:to="zfgn_MilestoneLiability_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_MilestonePaymentAmount" xlink:label="zfgn_MilestonePaymentAmount"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_MilestonePaymentAmount_lbl" xml:lang="en-US" id="id_9891417_1957406_3_1">Amount of payment due upon reaching milestone.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_MilestonePaymentAmount_lbl" xml:lang="en-US" id="id_9891417_1957406_1_1">Milestone Payment Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_MilestonePaymentAmount_lbl" xml:lang="en-US" id="id_9891417_1957406_2_1">Milestone payments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_MilestonePaymentAmount" xlink:to="zfgn_MilestonePaymentAmount_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MinimumMember" xlink:label="us-gaap_MinimumMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MinimumMember_lbl" xml:lang="en-US" id="id_9891417_1643741_1_1">Minimum [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MinimumMember_lbl" xml:lang="en-US" id="id_9891417_1643741_2_1">Minimum [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MinimumMember" xlink:to="us-gaap_MinimumMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MoneyMarketFundsMember" xlink:label="us-gaap_MoneyMarketFundsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MoneyMarketFundsMember_lbl" xml:lang="en-US" id="id_9891417_1637231_1_1">Money Market Funds [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MoneyMarketFundsMember_lbl" xml:lang="en-US" id="id_9891417_1637231_2_1">Money Market Funds [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MoneyMarketFundsMember" xlink:to="us-gaap_MoneyMarketFundsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_lbl" xml:lang="en-US" id="id_9891417_1649336_1_1">Net Cash Provided by (Used in) Financing Activities, Continuing Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_lbl" xml:lang="en-US" id="id_9891417_1649336_6_1">Net cash provided by financing activities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" id="id_9891417_1633620_1_1">Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" id="id_9891417_1633620_2_1">Cash flows from financing activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_lbl" xml:lang="en-US" id="id_9891417_1649062_1_1">Net Cash Provided by (Used in) Investing Activities, Continuing Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_lbl" xml:lang="en-US" id="id_9891417_1649062_6_1">Net cash used in investing activities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" id="id_9891417_1638471_1_1">Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" id="id_9891417_1638471_2_1">Cash flows from investing activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_lbl" xml:lang="en-US" id="id_9891417_1631616_1_1">Net Cash Provided by (Used in) Operating Activities, Continuing Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_lbl" xml:lang="en-US" id="id_9891417_1631616_6_1">Net cash used in operating activities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" id="id_9891417_1639627_1_1">Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" id="id_9891417_1639627_2_1">Cash flows from operating activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US" id="id_9891417_1644530_1_1">Net Income (Loss) Attributable to Parent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US" id="id_9891417_1644530_2_1">Net loss</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US" id="id_9891417_1644530_6_1">Net loss</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_NetIncomeLoss_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xml:lang="en-US" id="id_9891417_1644761_1_1">Net Income (Loss) Available to Common Stockholders, Basic</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xml:lang="en-US" id="id_9891417_1644761_2_1">Net loss attributable to common stockholders</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xml:lang="en-US" id="id_9891417_1644761_6_1">Net loss attributable to common stockholders</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_NetOperatingLossCarryForwardExpirationYearBegin" xlink:label="zfgn_NetOperatingLossCarryForwardExpirationYearBegin"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_NetOperatingLossCarryForwardExpirationYearBegin_lbl" xml:lang="en-US" id="id_9891417_1859082_3_1">Net Operating Loss Carry Forward Expiration Year Begin</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_NetOperatingLossCarryForwardExpirationYearBegin_lbl" xml:lang="en-US" id="id_9891417_1859082_1_1">Net Operating Loss Carry Forward Expiration Year Begin</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_NetOperatingLossCarryForwardExpirationYearBegin_lbl" xml:lang="en-US" id="id_9891417_1859082_2_1">Net operating loss carryforwards, beginning of expiration period</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_NetOperatingLossCarryForwardExpirationYearBegin" xlink:to="zfgn_NetOperatingLossCarryForwardExpirationYearBegin_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xml:lang="en-US" id="id_9891417_1642952_1_1">New Accounting Pronouncements, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xml:lang="en-US" id="id_9891417_1642952_2_1">Recently Issued and Adopted Accounting Pronouncements</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:to="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_NonemployeePerformanceBasedOptionsMember" xlink:label="zfgn_NonemployeePerformanceBasedOptionsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_NonemployeePerformanceBasedOptionsMember_lbl" xml:lang="en-US" id="id_9891417_1739271_3_1">Nonemployee Performance Based Options [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_NonemployeePerformanceBasedOptionsMember_lbl" xml:lang="en-US" id="id_9891417_1739271_1_1">Nonemployee Performance Based Options [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_NonemployeePerformanceBasedOptionsMember_lbl" xml:lang="en-US" id="id_9891417_1739271_2_1">Nonemployee Performance Based Options [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_NonemployeePerformanceBasedOptionsMember" xlink:to="zfgn_NonemployeePerformanceBasedOptionsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_NonemployeeServiceBasedOptionsMember" xlink:label="zfgn_NonemployeeServiceBasedOptionsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_NonemployeeServiceBasedOptionsMember_lbl" xml:lang="en-US" id="id_9891417_1707670_3_1">Nonemployee Service Based Options [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_NonemployeeServiceBasedOptionsMember_lbl" xml:lang="en-US" id="id_9891417_1707670_1_1">Nonemployee Service Based Options [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_NonemployeeServiceBasedOptionsMember_lbl" xml:lang="en-US" id="id_9891417_1707670_2_1">Nonemployee Service Based Options [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_NonemployeeServiceBasedOptionsMember" xlink:to="zfgn_NonemployeeServiceBasedOptionsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="us-gaap_NonoperatingIncomeExpense"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NonoperatingIncomeExpense_lbl" xml:lang="en-US" id="id_9891417_1645682_1_1">Nonoperating Income (Expense)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NonoperatingIncomeExpense_lbl" xml:lang="en-US" id="id_9891417_1645682_6_1">Total other income (expense), net</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_NonoperatingIncomeExpense_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NotesPayable" xlink:label="us-gaap_NotesPayable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NotesPayable_lbl" xml:lang="en-US" id="id_9891417_1647328_1_1">Notes Payable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NotesPayable_lbl" xml:lang="en-US" id="id_9891417_1647328_6_1">Notes payable</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NotesPayable" xlink:to="us-gaap_NotesPayable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NotesPayableCurrent" xlink:label="us-gaap_NotesPayableCurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NotesPayableCurrent_lbl" xml:lang="en-US" id="id_9891417_1647914_1_1">Notes Payable, Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NotesPayableCurrent_lbl" xml:lang="en-US" id="id_9891417_1647914_2_1">Notes payable, current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_NotesPayableCurrent_lbl" xml:lang="en-US" id="id_9891417_1647914_14_1">Less: current portion</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NotesPayableCurrent" xlink:to="us-gaap_NotesPayableCurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_NotesPayableNetOfCurrent" xlink:label="zfgn_NotesPayableNetOfCurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_NotesPayableNetOfCurrent_lbl" xml:lang="en-US" id="id_9891417_1974449_3_1">The net amount of total notes payable less the current portion of notes payable.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_NotesPayableNetOfCurrent_lbl" xml:lang="en-US" id="id_9891417_1974449_1_1">Notes Payable Net Of Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_NotesPayableNetOfCurrent_lbl" xml:lang="en-US" id="id_9891417_1974449_2_1">Notes payable, net of current portion</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="zfgn_NotesPayableNetOfCurrent_lbl" xml:lang="en-US" id="id_9891417_1974449_12_1">Notes payable, net of current portion</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_NotesPayableNetOfCurrent" xlink:to="zfgn_NotesPayableNetOfCurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_NumeratorAbstract" xlink:label="zfgn_NumeratorAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_NumeratorAbstract_lbl" xml:lang="en-US" id="id_9891417_1943599_3_1">Numerator [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_NumeratorAbstract_lbl" xml:lang="en-US" id="id_9891417_1943599_1_1">Numerator [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_NumeratorAbstract_lbl" xml:lang="en-US" id="id_9891417_1943599_2_1">Numerator:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_NumeratorAbstract" xlink:to="zfgn_NumeratorAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OfficeEquipmentMember" xlink:label="us-gaap_OfficeEquipmentMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OfficeEquipmentMember_lbl" xml:lang="en-US" id="id_9891417_1641298_1_1">Office Equipment [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OfficeEquipmentMember_lbl" xml:lang="en-US" id="id_9891417_1641298_2_1">Office Equipment [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OfficeEquipmentMember" xlink:to="us-gaap_OfficeEquipmentMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_OfficeSpaceLeaseMember" xlink:label="zfgn_OfficeSpaceLeaseMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_OfficeSpaceLeaseMember_lbl" xml:lang="en-US" id="id_9891417_1859704_3_1">Office Space Lease [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_OfficeSpaceLeaseMember_lbl" xml:lang="en-US" id="id_9891417_1859704_1_1">Office Space Lease [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_OfficeSpaceLeaseMember_lbl" xml:lang="en-US" id="id_9891417_1859704_2_1">Boston Office Space [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_OfficeSpaceLeaseMember" xlink:to="zfgn_OfficeSpaceLeaseMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="us-gaap_OperatingExpenses"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingExpenses_lbl" xml:lang="en-US" id="id_9891417_1648944_1_1">Operating Expenses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingExpenses_lbl" xml:lang="en-US" id="id_9891417_1648944_2_1">Operating expenses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_OperatingExpenses_lbl" xml:lang="en-US" id="id_9891417_1648944_6_1">Total operating expenses</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_OperatingExpenses_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="us-gaap_OperatingExpensesAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingExpensesAbstract_lbl" xml:lang="en-US" id="id_9891417_1632029_1_1">Operating Expenses [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingExpensesAbstract_lbl" xml:lang="en-US" id="id_9891417_1632029_2_1">Operating expenses:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_OperatingExpensesAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingIncomeLoss_lbl" xml:lang="en-US" id="id_9891417_1645424_1_1">Operating Income (Loss)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_OperatingIncomeLoss_lbl" xml:lang="en-US" id="id_9891417_1645424_6_1">Loss from operations</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_OperatingIncomeLoss_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue_lbl" xml:lang="en-US" id="id_9891417_1644876_1_1">Operating Leases, Future Minimum Payments Due</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue_lbl" xml:lang="en-US" id="id_9891417_1644876_6_1">Total</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDue_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_lbl" xml:lang="en-US" id="id_9891417_1644520_1_1">Operating Leases, Future Minimum Payments Due, Next Twelve Months</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_lbl" xml:lang="en-US" id="id_9891417_1644520_2_1">2016</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" xml:lang="en-US" id="id_9891417_1647220_1_1">Operating Leases, Future Minimum Payments, Due in Four Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" xml:lang="en-US" id="id_9891417_1647220_2_1">2019</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xml:lang="en-US" id="id_9891417_1647781_1_1">Operating Leases, Future Minimum Payments, Due in Three Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xml:lang="en-US" id="id_9891417_1647781_2_1">2018</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xml:lang="en-US" id="id_9891417_1644405_1_1">Operating Leases, Future Minimum Payments, Due in Two Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xml:lang="en-US" id="id_9891417_1644405_2_1">2017</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_OperatingLeasesNumberOfOptionsToExtendLease" xlink:label="zfgn_OperatingLeasesNumberOfOptionsToExtendLease"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_OperatingLeasesNumberOfOptionsToExtendLease_lbl" xml:lang="en-US" id="id_9891417_1840367_3_1">Operating Leases Number Of Options To Extend Lease</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_OperatingLeasesNumberOfOptionsToExtendLease_lbl" xml:lang="en-US" id="id_9891417_1840367_1_1">Operating Leases Number Of Options To Extend Lease</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_OperatingLeasesNumberOfOptionsToExtendLease_lbl" xml:lang="en-US" id="id_9891417_1840367_2_1">Number of options to extend lease</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_PercentageReductionResearchAndDevelopmentCosts_lbl" xml:lang="en-US" id="id_9891417_1699924_3_1">The percentage of research and development costs to be reduced.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_PercentageReductionResearchAndDevelopmentCosts_lbl" xml:lang="en-US" id="id_9891417_1699924_1_1">Percentage Reduction Research And Development Costs</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_PercentageReductionResearchAndDevelopmentCosts" xlink:to="zfgn_PercentageReductionResearchAndDevelopmentCosts_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_PercentageThresholdSaleOfVotingEquity" xlink:label="zfgn_PercentageThresholdSaleOfVotingEquity"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_PercentageThresholdSaleOfVotingEquity_lbl" xml:lang="en-US" id="id_9891417_1718180_3_1">The percentage threshold of equity retained by voting stockholders that will incur a fee if not maintained as part of an IPO, sale of assets, merger, reorganization, or sale of the Company's voting equity securities.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_PercentageThresholdSaleOfVotingEquity_lbl" xml:lang="en-US" id="id_9891417_1718180_1_1">Percentage Threshold Sale Of Voting Equity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_PercentageThresholdSaleOfVotingEquity_lbl" xml:lang="en-US" id="id_9891417_1718180_2_1">Sale of voting equity threshold</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_PercentageThresholdSaleOfVotingEquity" xlink:to="zfgn_PercentageThresholdSaleOfVotingEquity_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PlanNameAxis_lbl" xml:lang="en-US" id="id_9891417_1639657_1_1">Plan Name [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PlanNameAxis_lbl" xml:lang="en-US" id="id_9891417_1639657_2_1">Plan Name [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PlanNameDomain_lbl" xml:lang="en-US" id="id_9891417_1637683_1_1">Plan Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PlanNameDomain_lbl" xml:lang="en-US" id="id_9891417_1637683_2_1">Plan Name [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameDomain" xlink:to="us-gaap_PlanNameDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_PreCommercializationMilestonesMember" xlink:label="zfgn_PreCommercializationMilestonesMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_PreCommercializationMilestonesMember_lbl" xml:lang="en-US" id="id_9891417_1675013_3_1">Pre Commercialization Milestones [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_PreCommercializationMilestonesMember_lbl" xml:lang="en-US" id="id_9891417_1675013_1_1">Pre Commercialization Milestones [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_PreCommercializationMilestonesMember_lbl" xml:lang="en-US" id="id_9891417_1675013_2_1">Pre Commercialization Milestones [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_PreCommercializationMilestonesMember" xlink:to="zfgn_PreCommercializationMilestonesMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xml:lang="en-US" id="id_9891417_1642594_1_1">Preferred Stock, Par or Stated Value Per Share</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xml:lang="en-US" id="id_9891417_1642594_2_1">Preferred stock, par value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xml:lang="en-US" id="id_9891417_1642594_12_1">Preferred stock, par value per share</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockParOrStatedValuePerShare" xlink:to="us-gaap_PreferredStockParOrStatedValuePerShare_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="us-gaap_PreferredStockSharesAuthorized"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xml:lang="en-US" id="id_9891417_1639289_1_1">Preferred Stock, Shares Authorized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xml:lang="en-US" id="id_9891417_1639289_2_1">Preferred stock, shares authorized</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesAuthorized" xlink:to="us-gaap_PreferredStockSharesAuthorized_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="us-gaap_PreferredStockSharesIssued"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xml:lang="en-US" id="id_9891417_1640465_1_1">Preferred Stock, Shares Issued</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xml:lang="en-US" id="id_9891417_1640465_2_1">Preferred stock, shares issued</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesIssued" xlink:to="us-gaap_PreferredStockSharesIssued_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="us-gaap_PreferredStockSharesOutstanding"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xml:lang="en-US" id="id_9891417_1634872_1_1">Preferred Stock, Shares Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xml:lang="en-US" id="id_9891417_1634872_2_1">Preferred stock, shares outstanding</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesOutstanding" xlink:to="us-gaap_PreferredStockSharesOutstanding_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="us-gaap_PreferredStockValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockValue_lbl" xml:lang="en-US" id="id_9891417_1647540_1_1">Preferred Stock, Value, Issued</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockValue_lbl" xml:lang="en-US" id="id_9891417_1647540_2_1">Preferred stock; $0.001 par value per share; 5,000,000 shares authorized at December 31, 2015 and 2014; no shares issued and outstanding at December 31, 2015 and 2014</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockValue" xlink:to="us-gaap_PreferredStockValue_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_PremiumOnMarketableSecurities" xlink:label="zfgn_PremiumOnMarketableSecurities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_PremiumOnMarketableSecurities_lbl" xml:lang="en-US" id="id_9891417_1922210_3_1">The cash outflow associated with the premium paid on marketable securities.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_PremiumOnMarketableSecurities_lbl" xml:lang="en-US" id="id_9891417_1922210_1_1">Premium On Marketable Securities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="zfgn_PremiumOnMarketableSecurities_lbl" xml:lang="en-US" id="id_9891417_1922210_14_1">Premium on marketable securities, net</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_PremiumOnMarketableSecurities" xlink:to="zfgn_PremiumOnMarketableSecurities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xml:lang="en-US" id="id_9891417_1650984_1_1">Prepaid Expense and Other Assets, Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xml:lang="en-US" id="id_9891417_1650984_2_1">Prepaid expenses and other current assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering_lbl" xml:lang="en-US" id="id_9891417_1650988_1_1">Proceeds from Issuance Initial Public Offering</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering_lbl" xml:lang="en-US" id="id_9891417_1650988_2_1">Proceeds from public offerings, net of commissions and underwriting discounts</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:to="us-gaap_ProceedsFromIssuanceInitialPublicOffering_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_lbl" xml:lang="en-US" id="id_9891417_1649597_1_1">Proceeds from Issuance of Common Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_lbl" xml:lang="en-US" id="id_9891417_1649597_2_1">Proceeds from offering, net of commissions and underwriting discounts</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock" xlink:label="us-gaap_ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock_lbl" xml:lang="en-US" id="id_9891417_1649980_1_1">Proceeds from Issuance of Redeemable Convertible Preferred Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock_lbl" xml:lang="en-US" id="id_9891417_1649980_2_1">Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock" xlink:to="us-gaap_ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSecuredDebt" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt_lbl" xml:lang="en-US" id="id_9891417_1648972_1_1">Proceeds from Issuance of Secured Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt_lbl" xml:lang="en-US" id="id_9891417_1648972_2_1">Proceeds from issuance of promissory notes</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfSecuredDebt" xlink:to="us-gaap_ProceedsFromIssuanceOfSecuredDebt_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:label="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_lbl" xml:lang="en-US" id="id_9891417_1650105_1_1">Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_lbl" xml:lang="en-US" id="id_9891417_1650105_2_1">Proceeds from exercise of common stock options and employee stock purchase plan</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:to="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xml:lang="en-US" id="id_9891417_1650991_1_1">Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xml:lang="en-US" id="id_9891417_1650991_2_1">Proceeds from maturities of marketable securities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:to="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromNotesPayable" xlink:label="us-gaap_ProceedsFromNotesPayable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromNotesPayable_lbl" xml:lang="en-US" id="id_9891417_1651378_1_1">Proceeds from Notes Payable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromNotesPayable_lbl" xml:lang="en-US" id="id_9891417_1651378_2_1">Proceeds from issuance of notes payable, net of issuance costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromNotesPayable" xlink:to="us-gaap_ProceedsFromNotesPayable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="us-gaap_ProceedsFromStockOptionsExercised"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xml:lang="en-US" id="id_9891417_1649976_1_1">Proceeds from Stock Options Exercised</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xml:lang="en-US" id="id_9891417_1649976_2_1">Proceeds from exercise of common stock options</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromStockOptionsExercised" xlink:to="us-gaap_ProceedsFromStockOptionsExercised_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_ProductCommercializationMilestonesMember" xlink:label="zfgn_ProductCommercializationMilestonesMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_ProductCommercializationMilestonesMember_lbl" xml:lang="en-US" id="id_9891417_1658656_3_1">Product Commercialization Milestones [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_ProductCommercializationMilestonesMember_lbl" xml:lang="en-US" id="id_9891417_1658656_1_1">Product Commercialization Milestones [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_ProductCommercializationMilestonesMember_lbl" xml:lang="en-US" id="id_9891417_1658656_2_1">Product Commercialization Milestones [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_ProductCommercializationMilestonesMember" xlink:to="zfgn_ProductCommercializationMilestonesMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="us-gaap_PropertyPlantAndEquipmentAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentAbstract_lbl" xml:lang="en-US" id="id_9891417_1643397_1_1">Property, Plant and Equipment [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentAbstract_lbl" xml:lang="en-US" id="id_9891417_1643397_2_1">Property, Plant and Equipment [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentAbstract" xlink:to="us-gaap_PropertyPlantAndEquipmentAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xml:lang="en-US" id="id_9891417_1634505_1_1">Property, Plant and Equipment, Type [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xml:lang="en-US" id="id_9891417_1634505_2_1">Property, Plant and Equipment, Type [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_PropertyPlantAndEquipmentCapitalizedInterestCostsAbstract" xlink:label="zfgn_PropertyPlantAndEquipmentCapitalizedInterestCostsAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_PropertyPlantAndEquipmentCapitalizedInterestCostsAbstract_lbl" xml:lang="en-US" id="id_9891417_1742800_3_1">Property Plant And Equipment Capitalized Interest Costs [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_PropertyPlantAndEquipmentCapitalizedInterestCostsAbstract_lbl" xml:lang="en-US" id="id_9891417_1742800_1_1">Property Plant And Equipment Capitalized Interest Costs [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_PropertyPlantAndEquipmentCapitalizedInterestCostsAbstract_lbl" xml:lang="en-US" id="id_9891417_1742800_2_1">Property Plant And Equipment Capitalized Interest Costs [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_PropertyPlantAndEquipmentCapitalizedInterestCostsAbstract" xlink:to="zfgn_PropertyPlantAndEquipmentCapitalizedInterestCostsAbstract_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_lbl" xml:lang="en-US" id="id_9891417_1637277_1_1">Property, Plant and Equipment Disclosure [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_lbl" xml:lang="en-US" id="id_9891417_1637277_2_1">Property and Equipment, net</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xml:lang="en-US" id="id_9891417_1651381_1_1">Property, Plant and Equipment, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xml:lang="en-US" id="id_9891417_1651381_2_1">Property and equipment, gross</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentGross" xlink:to="us-gaap_PropertyPlantAndEquipmentGross_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xml:lang="en-US" id="id_9891417_1642195_1_1">Property, Plant and Equipment [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xml:lang="en-US" id="id_9891417_1642195_2_1">Property, Plant and Equipment [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xml:lang="en-US" id="id_9891417_1649598_1_1">Property, Plant and Equipment, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xml:lang="en-US" id="id_9891417_1649598_2_1">Property and equipment, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xml:lang="en-US" id="id_9891417_1649598_6_1">Property and equipment, net</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xml:lang="en-US" id="id_9891417_1634506_1_1">Property, Plant and Equipment, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xml:lang="en-US" id="id_9891417_1634506_2_1">Property and Equipment</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xml:lang="en-US" id="id_9891417_1638511_1_1">Property, Plant and Equipment [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xml:lang="en-US" id="id_9891417_1638511_2_1">Schedule of Property Plant and Equipment Net</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xml:lang="en-US" id="id_9891417_1637279_1_1">Property, Plant and Equipment, Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xml:lang="en-US" id="id_9891417_1637279_2_1">Property, Plant and Equipment, Type [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xml:lang="en-US" id="id_9891417_1634075_1_1">Property, Plant and Equipment, Useful Life</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xml:lang="en-US" id="id_9891417_1634075_2_1">Estimated useful life</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xml:lang="en-US" id="id_9891417_1634075_12_1">Property and equipment, Useful Life</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_QualifiedIPOMember" xlink:label="zfgn_QualifiedIPOMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_QualifiedIPOMember_lbl" xml:lang="en-US" id="id_9891417_1695070_3_1">Qualified IPO [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_QualifiedIPOMember_lbl" xml:lang="en-US" id="id_9891417_1695070_1_1">Qualified IPO [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_QualifiedIPOMember_lbl" xml:lang="en-US" id="id_9891417_1695070_2_1">Qualified IPO [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_QualifiedIPOMember" xlink:to="zfgn_QualifiedIPOMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_QuarterlyFinancialInformationDisclosureAbstract" xlink:label="us-gaap_QuarterlyFinancialInformationDisclosureAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_QuarterlyFinancialInformationDisclosureAbstract_lbl" xml:lang="en-US" id="id_9891417_1642602_1_1">Quarterly Financial Information Disclosure [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_QuarterlyFinancialInformationDisclosureAbstract_lbl" xml:lang="en-US" id="id_9891417_1642602_2_1">Quarterly Financial Information Disclosure [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_QuarterlyFinancialInformationDisclosureAbstract" xlink:to="us-gaap_QuarterlyFinancialInformationDisclosureAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_QuarterlyFinancialInformationTextBlock" xlink:label="us-gaap_QuarterlyFinancialInformationTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_QuarterlyFinancialInformationTextBlock_lbl" xml:lang="en-US" id="id_9891417_1637710_1_1">Quarterly Financial Information [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_QuarterlyFinancialInformationTextBlock_lbl" xml:lang="en-US" id="id_9891417_1637710_2_1">Quarterly Financial Data (Unaudited)</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_QuarterlyFinancialInformationTextBlock" xlink:to="us-gaap_QuarterlyFinancialInformationTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RangeAxis" xlink:label="us-gaap_RangeAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RangeAxis_lbl" xml:lang="en-US" id="id_9891417_1639304_1_1">Range [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RangeAxis_lbl" xml:lang="en-US" id="id_9891417_1639304_2_1">Range [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RangeMember_lbl" xml:lang="en-US" id="id_9891417_1634888_1_1">Range [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RangeMember_lbl" xml:lang="en-US" id="id_9891417_1634888_2_1">Range [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_RangeMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RedeemableConvertiblePreferredStockMember" xlink:label="us-gaap_RedeemableConvertiblePreferredStockMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RedeemableConvertiblePreferredStockMember_lbl" xml:lang="en-US" id="id_9891417_1632459_1_1">Redeemable Convertible Preferred Stock [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RedeemableConvertiblePreferredStockMember_lbl" xml:lang="en-US" id="id_9891417_1632459_2_1">Redeemable Convertible Preferred Stock [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RedeemableConvertiblePreferredStockMember" xlink:to="us-gaap_RedeemableConvertiblePreferredStockMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_RedeemablePreferredStockConvertedToCommonStock" xlink:label="zfgn_RedeemablePreferredStockConvertedToCommonStock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_RedeemablePreferredStockConvertedToCommonStock_lbl" xml:lang="en-US" id="id_9891417_1834954_3_1">The number of shares of redeemable convertible preferred stock converted to common stock during the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_RedeemablePreferredStockConvertedToCommonStock_lbl" xml:lang="en-US" id="id_9891417_1834954_1_1">Redeemable Preferred Stock Converted To Common Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_RedeemablePreferredStockConvertedToCommonStock_lbl" xml:lang="en-US" id="id_9891417_1834954_2_1">Conversion of redeemable convertible preferred stock to common stock, shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_RedeemablePreferredStockConvertedToCommonStock" xlink:to="zfgn_RedeemablePreferredStockConvertedToCommonStock_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_RedeemablePreferredStockConvertibleIntoCommonStockValue" xlink:label="zfgn_RedeemablePreferredStockConvertibleIntoCommonStockValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_RedeemablePreferredStockConvertibleIntoCommonStockValue_lbl" xml:lang="en-US" id="id_9891417_1849474_3_1">The value of redeemable preferred stock converted into common stock during the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_RedeemablePreferredStockConvertibleIntoCommonStockValue_lbl" xml:lang="en-US" id="id_9891417_1849474_1_1">Redeemable Preferred Stock Convertible Into Common Stock Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="zfgn_RedeemablePreferredStockConvertibleIntoCommonStockValue_lbl" xml:lang="en-US" id="id_9891417_1849474_14_1">Conversion of redeemable convertible preferred stock to common stock, value</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_RedeemablePreferredStockConvertibleIntoCommonStockValue" xlink:to="zfgn_RedeemablePreferredStockConvertibleIntoCommonStockValue_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepaymentsOfNotesPayable" xlink:label="us-gaap_RepaymentsOfNotesPayable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RepaymentsOfNotesPayable_lbl" xml:lang="en-US" id="id_9891417_1644375_1_1">Repayments of Notes Payable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_RepaymentsOfNotesPayable_lbl" xml:lang="en-US" id="id_9891417_1644375_14_1">Repayments of notes payable</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RepaymentsOfNotesPayable" xlink:to="us-gaap_RepaymentsOfNotesPayable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ResearchAndDevelopmentAbstract" xlink:label="us-gaap_ResearchAndDevelopmentAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ResearchAndDevelopmentAbstract_lbl" xml:lang="en-US" id="id_9891417_1637296_1_1">Research and Development [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ResearchAndDevelopmentAbstract_lbl" xml:lang="en-US" id="id_9891417_1637296_2_1">Research and Development [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ResearchAndDevelopmentAbstract" xlink:to="us-gaap_ResearchAndDevelopmentAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis" xlink:label="us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis"/>
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    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_SecondOfferingPeriodEndDate" xlink:label="zfgn_SecondOfferingPeriodEndDate"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1642255_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_lbl" xml:lang="en-US" id="id_9891417_1635425_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_lbl" xml:lang="en-US" id="id_9891417_1650874_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_lbl" xml:lang="en-US" id="id_9891417_1650874_2_1">Aggregate intrinsic value of stock options exercised</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xml:lang="en-US" id="id_9891417_1633736_14_1">Shares issuable under options, forfeited</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xml:lang="en-US" id="id_9891417_1640581_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xml:lang="en-US" id="id_9891417_1640581_2_1">Shares issuable under options, granted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xml:lang="en-US" id="id_9891417_1640581_12_1">Stock based compensation, stock options granted</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US" id="id_9891417_1641797_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US" id="id_9891417_1641797_2_1">Weighted average grant-date fair value of stock options granted</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares_lbl" xml:lang="en-US" id="id_9891417_1633737_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares_lbl" xml:lang="en-US" id="id_9891417_1633737_2_1">Number of outstanding unvested shares held by nonemployees</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOtherIncreasesDecreasesInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOtherIncreasesDecreasesInPeriod"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOtherIncreasesDecreasesInPeriod_lbl" xml:lang="en-US" id="id_9891417_1641360_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Other Increases (Decreases) in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOtherIncreasesDecreasesInPeriod_lbl" xml:lang="en-US" id="id_9891417_1641360_2_1">Shares added to plan</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOtherIncreasesDecreasesInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOtherIncreasesDecreasesInPeriod_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xml:lang="en-US" id="id_9891417_1651525_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xml:lang="en-US" id="id_9891417_1651525_4_1">Aggregate intrinsic value, ending balance</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xml:lang="en-US" id="id_9891417_1632583_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xml:lang="en-US" id="id_9891417_1632583_4_1">Shares issuable under options, ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xml:lang="en-US" id="id_9891417_1632583_5_1">Shares issuable under options, beginning balance</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1634132_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1634132_4_1">Weighted-average exercise price, ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1634132_5_1">Weighted-average exercise price, beginning balance</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_lbl" xml:lang="en-US" id="id_9891417_1634936_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_lbl" xml:lang="en-US" id="id_9891417_1634936_2_1">Average remaining contractual life</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_lbl" xml:lang="en-US" id="id_9891417_1648736_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_lbl" xml:lang="en-US" id="id_9891417_1648736_2_1">Aggregate intrinsic value, options vested and expected to vest</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_lbl" xml:lang="en-US" id="id_9891417_1643442_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_lbl" xml:lang="en-US" id="id_9891417_1643442_2_1">Shares issuable under options, options vested and expected to vest</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1636531_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_lbl" xml:lang="en-US" id="id_9891417_1644249_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_lbl" xml:lang="en-US" id="id_9891417_1644249_2_1">Average remaining contractual life, options vested and expected to vest</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_lbl" xml:lang="en-US" id="id_9891417_1638568_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_lbl" xml:lang="en-US" id="id_9891417_1638568_2_1">Options purchase price of common stock, percent of fair market value</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xml:lang="en-US" id="id_9891417_1634939_1_1">Equity Award [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xml:lang="en-US" id="id_9891417_1634939_2_1">Equity Award [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1641363_1_1">Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1641363_2_1">Weighted-average exercise price, exercised</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1635427_1_1">Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1635427_2_1">Weighted-average exercise price, forfeited</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1638569_1_1">Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_9891417_1638569_2_1">Weighted-average exercise price, granted</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" xml:lang="en-US" id="id_9891417_1641799_1_1">Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" xml:lang="en-US" id="id_9891417_1641799_2_1">Accounting for Stock-Based Compensation</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:to="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharesIssuedPricePerShare_lbl" xml:lang="en-US" id="id_9891417_1642714_1_1">Shares Issued, Price Per Share</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharesIssuedPricePerShare_lbl" xml:lang="en-US" id="id_9891417_1642714_2_1">Common stock issued price per share</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharesIssuedPricePerShare" xlink:to="us-gaap_SharesIssuedPricePerShare_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="us-gaap_SharesOutstanding"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharesOutstanding_lbl" xml:lang="en-US" id="id_9891417_1637831_1_1">Shares, Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_SharesOutstanding_lbl" xml:lang="en-US" id="id_9891417_1637831_4_1">Ending balance, shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_SharesOutstanding_lbl" xml:lang="en-US" id="id_9891417_1637831_5_1">Beginning balance, shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharesOutstanding" xlink:to="us-gaap_SharesOutstanding_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock_lbl" xml:lang="en-US" id="id_9891417_1643028_1_1">Significant Accounting Policies [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock_lbl" xml:lang="en-US" id="id_9891417_1643028_2_1">Summary of Significant Accounting Policies</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SignificantAccountingPoliciesTextBlock" xlink:to="us-gaap_SignificantAccountingPoliciesTextBlock_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StateAndLocalJurisdictionMember_lbl" xml:lang="en-US" id="id_9891417_1641051_1_1">State and Local Jurisdiction [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StateAndLocalJurisdictionMember_lbl" xml:lang="en-US" id="id_9891417_1641051_2_1">State and Local Jurisdiction [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StateAndLocalJurisdictionMember" xlink:to="us-gaap_StateAndLocalJurisdictionMember_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementClassOfStockAxis_lbl" xml:lang="en-US" id="id_9891417_1641810_1_1">Class of Stock [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StatementClassOfStockAxis_lbl" xml:lang="en-US" id="id_9891417_1641810_2_1">Class of Stock [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_StatementClassOfStockAxis_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xml:lang="en-US" id="id_9891417_1643450_1_1">Equity Components [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xml:lang="en-US" id="id_9891417_1643450_2_1">Equity Components [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_StatementEquityComponentsAxis_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementGeographicalAxis_lbl" xml:lang="en-US" id="id_9891417_1641811_1_1">Geographical [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StatementGeographicalAxis_lbl" xml:lang="en-US" id="id_9891417_1641811_2_1">Geographical [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementGeographicalAxis" xlink:to="us-gaap_StatementGeographicalAxis_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementLineItems_lbl" xml:lang="en-US" id="id_9891417_1641812_1_1">Statement [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StatementLineItems_lbl" xml:lang="en-US" id="id_9891417_1641812_2_1">Statement [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementLineItems_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xml:lang="en-US" id="id_9891417_1643038_1_1">Statement of Cash Flows [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xml:lang="en-US" id="id_9891417_1643038_2_1">Statement of Cash Flows [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_StatementOfCashFlowsAbstract_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_lbl" xml:lang="en-US" id="id_9891417_1640591_1_1">Statement of Financial Position [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_lbl" xml:lang="en-US" id="id_9891417_1640591_2_1">Statement of Financial Position [Abstract]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract_lbl" xml:lang="en-US" id="id_9891417_1643451_2_1">Statement of Stockholders' Equity [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="us-gaap_StatementOfStockholdersEquityAbstract_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StatementScenarioAxis_lbl" xml:lang="en-US" id="id_9891417_1640593_2_1">Scenario [Axis]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xml:lang="en-US" id="id_9891417_1634143_1_1">Stockholders' Equity Attributable to Parent [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xml:lang="en-US" id="id_9891417_1634143_2_1">Stockholders' equity:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_StockholdersEquityAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl" xml:lang="en-US" id="id_9891417_1642264_1_1">Stockholders' Equity Note Disclosure [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl" xml:lang="en-US" id="id_9891417_1642264_2_1">Stockholders' Equity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:to="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockholdersEquityNoteStockSplitConversionRatio1" xlink:label="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1_lbl" xml:lang="en-US" id="id_9891417_1642265_1_1">Stockholders' Equity Note, Stock Split, Conversion Ratio</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1_lbl" xml:lang="en-US" id="id_9891417_1642265_2_1">Convertible preferred stock, conversion ratio</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1" xlink:to="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockholdersEquityReverseStockSplit" xlink:label="us-gaap_StockholdersEquityReverseStockSplit"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquityReverseStockSplit_lbl" xml:lang="en-US" id="id_9891417_1638248_1_1">Stockholders' Equity, Reverse Stock Split</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockholdersEquityReverseStockSplit_lbl" xml:lang="en-US" id="id_9891417_1638248_2_1">Reverse stock split, description</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityReverseStockSplit" xlink:to="us-gaap_StockholdersEquityReverseStockSplit_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentShares" xlink:label="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentShares"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentShares_lbl" xml:lang="en-US" id="id_9891417_1853316_3_1">The number of shares issued during the period in lieu of milestone payments.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentShares_lbl" xml:lang="en-US" id="id_9891417_1853316_1_1">Stock Issued During Period In Lieu Of Milestone Payment Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentShares_lbl" xml:lang="en-US" id="id_9891417_1853316_2_1">Issuance of common stock in lieu of milestone payment, shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentShares" xlink:to="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentShares_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentValue" xlink:label="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentValue_lbl" xml:lang="en-US" id="id_9891417_1833530_3_1">The value of stock issued during the period in lieu of milestone payments.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentValue_lbl" xml:lang="en-US" id="id_9891417_1833530_1_1">Stock Issued During Period In Lieu Of Milestone Payment Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentValue_lbl" xml:lang="en-US" id="id_9891417_1833530_2_1">Issuance of common stock in lieu of milestone payment</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentValue" xlink:to="zfgn_StockIssuedDuringPeriodInLieuOfMilestonePaymentValue_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" xml:lang="en-US" id="id_9891417_1633033_1_1">Stock Issued During Period, Shares, New Issues</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" xml:lang="en-US" id="id_9891417_1633033_2_1">Common stock issued</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" xml:lang="en-US" id="id_9891417_1633033_12_1">Issuance of common stock, shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_lbl" xml:lang="en-US" id="id_9891417_1643522_1_1">Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_lbl" xml:lang="en-US" id="id_9891417_1643522_2_1">Issuance of restricted stock, shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xml:lang="en-US" id="id_9891417_1640611_1_1">Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xml:lang="en-US" id="id_9891417_1640611_2_1">Stock-based awards , shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:to="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xml:lang="en-US" id="id_9891417_1642361_1_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xml:lang="en-US" id="id_9891417_1642361_2_1">Issuance of common stock upon exercise of stock options, shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xml:lang="en-US" id="id_9891417_1642361_14_1">Shares issuable under options, exercised</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_StockIssuedDuringPeriodSharesStockOptionsExercisedAndEmployeeStockPurchasePlans" xlink:label="zfgn_StockIssuedDuringPeriodSharesStockOptionsExercisedAndEmployeeStockPurchasePlans"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_StockIssuedDuringPeriodSharesStockOptionsExercisedAndEmployeeStockPurchasePlans_lbl" xml:lang="en-US" id="id_9891417_1667060_3_1">The number of shares issued during the period upon exercise of stock options and stock purchase plans.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_StockIssuedDuringPeriodSharesStockOptionsExercisedAndEmployeeStockPurchasePlans_lbl" xml:lang="en-US" id="id_9891417_1667060_1_1">Stock Issued During Period Shares Stock Options Exercised And Employee Stock Purchase Plans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_StockIssuedDuringPeriodSharesStockOptionsExercisedAndEmployeeStockPurchasePlans_lbl" xml:lang="en-US" id="id_9891417_1667060_2_1">Issuance of common stock upon exercise of stock options and employee stock purchase plan, shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_StockIssuedDuringPeriodSharesStockOptionsExercisedAndEmployeeStockPurchasePlans" xlink:to="zfgn_StockIssuedDuringPeriodSharesStockOptionsExercisedAndEmployeeStockPurchasePlans_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" xml:lang="en-US" id="id_9891417_1645146_1_1">Stock Issued During Period, Value, New Issues</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" xml:lang="en-US" id="id_9891417_1645146_2_1">Issuance of common stock</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:to="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_lbl" xml:lang="en-US" id="id_9891417_1645763_1_1">Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_lbl" xml:lang="en-US" id="id_9891417_1645763_2_1">Issuance of restricted stock</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" xlink:to="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl" xml:lang="en-US" id="id_9891417_1644722_1_1">Stock Issued During Period, Value, Stock Options Exercised</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl" xml:lang="en-US" id="id_9891417_1644722_2_1">Issuance of common stock upon exercise of stock options, value</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:to="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_StockIssuedDuringPeriodValueStockOptionsExercisedAndEmployeeStockPurchasePlan" xlink:label="zfgn_StockIssuedDuringPeriodValueStockOptionsExercisedAndEmployeeStockPurchasePlan"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_StockIssuedDuringPeriodValueStockOptionsExercisedAndEmployeeStockPurchasePlan_lbl" xml:lang="en-US" id="id_9891417_1857299_3_1">The value of stock issued during the period upon exercise of stock options and stock purchase plans.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_StockIssuedDuringPeriodValueStockOptionsExercisedAndEmployeeStockPurchasePlan_lbl" xml:lang="en-US" id="id_9891417_1857299_1_1">Stock Issued During Period Value Stock Options Exercised And Employee Stock Purchase Plan</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_StockIssuedDuringPeriodValueStockOptionsExercisedAndEmployeeStockPurchasePlan_lbl" xml:lang="en-US" id="id_9891417_1857299_2_1">Issuance of common stock upon exercise of stock options and employee stock purchase plan</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_StockIssuedDuringPeriodValueStockOptionsExercisedAndEmployeeStockPurchasePlan" xlink:to="zfgn_StockIssuedDuringPeriodValueStockOptionsExercisedAndEmployeeStockPurchasePlan_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xml:lang="en-US" id="id_9891417_1640210_1_1">Stock Repurchased and Retired During Period, Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xml:lang="en-US" id="id_9891417_1640210_14_1">Repurchase and retirement of common stock, at cost</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_SubsequentLicensedProductMember" xlink:label="zfgn_SubsequentLicensedProductMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_SubsequentLicensedProductMember_lbl" xml:lang="en-US" id="id_9891417_1909013_3_1">Subsequent Licensed Product [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_SubsequentLicensedProductMember_lbl" xml:lang="en-US" id="id_9891417_1909013_1_1">Subsequent Licensed Product [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_SubsequentLicensedProductMember_lbl" xml:lang="en-US" id="id_9891417_1909013_2_1">Subsequent Licensed Product [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_SubsequentLicensedProductMember" xlink:to="zfgn_SubsequentLicensedProductMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="us-gaap_SubsidiarySaleOfStockAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xml:lang="en-US" id="id_9891417_1637033_1_1">Sale of Stock [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xml:lang="en-US" id="id_9891417_1637033_2_1">Sale of Stock [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SubsidiarySaleOfStockAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SummaryOfValuationAllowanceTextBlock" xlink:label="us-gaap_SummaryOfValuationAllowanceTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SummaryOfValuationAllowanceTextBlock_lbl" xml:lang="en-US" id="id_9891417_1641058_1_1">Summary of Valuation Allowance [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SummaryOfValuationAllowanceTextBlock_lbl" xml:lang="en-US" id="id_9891417_1641058_2_1">Summary Changes in the Valuation Allowance for Deferred Tax Assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SummaryOfValuationAllowanceTextBlock" xlink:to="us-gaap_SummaryOfValuationAllowanceTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xml:lang="en-US" id="id_9891417_1643862_1_1">Supplemental Cash Flow Information [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xml:lang="en-US" id="id_9891417_1643862_2_1">Supplemental disclosure of cash flow information:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="us-gaap_SupplementalCashFlowInformationAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TaxCreditCarryforwardAxis" xlink:label="us-gaap_TaxCreditCarryforwardAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TaxCreditCarryforwardAxis_lbl" xml:lang="en-US" id="id_9891417_1638254_1_1">Tax Credit Carryforward [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TaxCreditCarryforwardAxis_lbl" xml:lang="en-US" id="id_9891417_1638254_2_1">Tax Credit Carryforward [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxCreditCarryforwardAxis" xlink:to="us-gaap_TaxCreditCarryforwardAxis_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_TaxCreditCarryForwardExpirationYearStart_lbl" xml:lang="en-US" id="id_9891417_1866661_3_1">Tax Credit Carry Forward Expiration Year Start</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_TaxCreditCarryForwardExpirationYearStart_lbl" xml:lang="en-US" id="id_9891417_1866661_1_1">Tax Credit Carry Forward Expiration Year Start</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_TaxCreditCarryForwardExpirationYearStart_lbl" xml:lang="en-US" id="id_9891417_1866661_2_1">Research and development tax credit carryforwards, beginning of expiration period</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_TaxCreditCarryForwardExpirationYearStart" xlink:to="zfgn_TaxCreditCarryForwardExpirationYearStart_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TaxCreditCarryforwardNameDomain_lbl" xml:lang="en-US" id="id_9891417_1644267_1_1">Tax Credit Carryforward, Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TaxCreditCarryforwardNameDomain_lbl" xml:lang="en-US" id="id_9891417_1644267_2_1">Tax Credit Carryforward, Name [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxCreditCarryforwardNameDomain" xlink:to="us-gaap_TaxCreditCarryforwardNameDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TemporaryEquityAccretionToRedemptionValueAdjustment" xlink:label="us-gaap_TemporaryEquityAccretionToRedemptionValueAdjustment"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TemporaryEquityAccretionToRedemptionValueAdjustment_lbl" xml:lang="en-US" id="id_9891417_1648114_1_1">Temporary Equity, Accretion to Redemption Value, Adjustment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TemporaryEquityAccretionToRedemptionValueAdjustment_lbl" xml:lang="en-US" id="id_9891417_1648114_2_1">Accretion of redeemable convertible preferred stock to redemption values</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_TemporaryEquityAccretionToRedemptionValueAdjustment_lbl" xml:lang="en-US" id="id_9891417_1648114_14_1">Accretion of redeemable convertible preferred stock to redemption value</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TemporaryEquityAccretionToRedemptionValueAdjustment" xlink:to="us-gaap_TemporaryEquityAccretionToRedemptionValueAdjustment_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TemporaryEquitySharesOutstanding" xlink:label="us-gaap_TemporaryEquitySharesOutstanding"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TemporaryEquitySharesOutstanding_lbl" xml:lang="en-US" id="id_9891417_1631804_1_1">Temporary Equity, Shares Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_TemporaryEquitySharesOutstanding_lbl" xml:lang="en-US" id="id_9891417_1631804_4_1">Temporary equity, ending balance, shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_TemporaryEquitySharesOutstanding_lbl" xml:lang="en-US" id="id_9891417_1631804_5_1">Temporary equity, beginning balance, shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TemporaryEquitySharesOutstanding" xlink:to="us-gaap_TemporaryEquitySharesOutstanding_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues" xlink:label="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_lbl" xml:lang="en-US" id="id_9891417_1646963_1_1">Temporary Equity, Stock Issued During Period, Value, New Issues</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_lbl" xml:lang="en-US" id="id_9891417_1646963_2_1">Issuance of redeemable convertible preferred stock, value</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues" xlink:to="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital" xlink:label="us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital_lbl" xml:lang="en-US" id="id_9891417_1647734_1_1">Temporary Equity, Par Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital_lbl" xml:lang="en-US" id="id_9891417_1647734_4_1">Temporary equity, ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital_lbl" xml:lang="en-US" id="id_9891417_1647734_5_1">Temporary equity, beginning balance</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital" xlink:to="us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_TermLoanAMember" xlink:label="zfgn_TermLoanAMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_TermLoanAMember_lbl" xml:lang="en-US" id="id_9891417_1677581_3_1">Term Loan A [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_TermLoanAMember_lbl" xml:lang="en-US" id="id_9891417_1677581_1_1">Term Loan A [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_TermLoanAMember_lbl" xml:lang="en-US" id="id_9891417_1677581_2_1">Term Loan A [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_TermLoanAMember" xlink:to="zfgn_TermLoanAMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_TermLoanBAndCMember" xlink:label="zfgn_TermLoanBAndCMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_TermLoanBAndCMember_lbl" xml:lang="en-US" id="id_9891417_1676225_3_1">Term Loan B And C [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_TermLoanBAndCMember_lbl" xml:lang="en-US" id="id_9891417_1676225_1_1">Term Loan B And C [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_TermLoanBAndCMember_lbl" xml:lang="en-US" id="id_9891417_1676225_2_1">Term Loan B and C [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_TermLoanBAndCMember" xlink:to="zfgn_TermLoanBAndCMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_TermLoanBMember" xlink:label="zfgn_TermLoanBMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_TermLoanBMember_lbl" xml:lang="en-US" id="id_9891417_1911134_3_1">Term Loan B [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_TermLoanBMember_lbl" xml:lang="en-US" id="id_9891417_1911134_1_1">Term Loan B [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_TermLoanBMember_lbl" xml:lang="en-US" id="id_9891417_1911134_2_1">Term Loan B [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_TermLoanBMember" xlink:to="zfgn_TermLoanBMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_TermLoanCMember" xlink:label="zfgn_TermLoanCMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_TermLoanCMember_lbl" xml:lang="en-US" id="id_9891417_1665150_3_1">Term Loan C [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_TermLoanCMember_lbl" xml:lang="en-US" id="id_9891417_1665150_1_1">Term Loan C [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_TermLoanCMember_lbl" xml:lang="en-US" id="id_9891417_1665150_2_1">Term Loan C [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_TermLoanCMember" xlink:to="zfgn_TermLoanCMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_ThirdOfferingPeriodEndDate" xlink:label="zfgn_ThirdOfferingPeriodEndDate"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_ThirdOfferingPeriodEndDate_lbl" xml:lang="en-US" id="id_9891417_2012177_3_1">Third offering period end date.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_ThirdOfferingPeriodEndDate_lbl" xml:lang="en-US" id="id_9891417_2012177_1_1">Third Offering Period End Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_ThirdOfferingPeriodEndDate_lbl" xml:lang="en-US" id="id_9891417_2012177_2_1">End date of third offering period</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_ThirdOfferingPeriodEndDate" xlink:to="zfgn_ThirdOfferingPeriodEndDate_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_ThirdOfferingPeriodStartDate" xlink:label="zfgn_ThirdOfferingPeriodStartDate"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_ThirdOfferingPeriodStartDate_lbl" xml:lang="en-US" id="id_9891417_2012175_3_1">Third offering period start date.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_ThirdOfferingPeriodStartDate_lbl" xml:lang="en-US" id="id_9891417_2012175_1_1">Third Offering Period Start Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_ThirdOfferingPeriodStartDate_lbl" xml:lang="en-US" id="id_9891417_2012175_2_1">Commencement date of third offering period</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_ThirdOfferingPeriodStartDate" xlink:to="zfgn_ThirdOfferingPeriodStartDate_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_TradingSymbol" xlink:label="dei_TradingSymbol"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_TradingSymbol_lbl" xml:lang="en-US" id="id_9891417_1643125_1_1">Trading Symbol</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="dei_TradingSymbol_lbl" xml:lang="en-US" id="id_9891417_1643125_2_1">Trading Symbol</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_TradingSymbol" xlink:to="dei_TradingSymbol_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_TwoThousandAndFourteenEmployeeStockPurchasePlanMember" xlink:label="zfgn_TwoThousandAndFourteenEmployeeStockPurchasePlanMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_TwoThousandAndFourteenEmployeeStockPurchasePlanMember_lbl" xml:lang="en-US" id="id_9891417_1937717_3_1">Two Thousand And Fourteen Employee Stock Purchase Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_TwoThousandAndFourteenEmployeeStockPurchasePlanMember_lbl" xml:lang="en-US" id="id_9891417_1937717_1_1">Two Thousand And Fourteen Employee Stock Purchase Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_TwoThousandAndFourteenEmployeeStockPurchasePlanMember_lbl" xml:lang="en-US" id="id_9891417_1937717_2_1">2014 Employee Stock Purchase Plan [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_TwoThousandAndFourteenEmployeeStockPurchasePlanMember" xlink:to="zfgn_TwoThousandAndFourteenEmployeeStockPurchasePlanMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_TwoThousandFourteenStockOptionMember" xlink:label="zfgn_TwoThousandFourteenStockOptionMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_TwoThousandFourteenStockOptionMember_lbl" xml:lang="en-US" id="id_9891417_1863081_3_1">Two Thousand Fourteen Stock Option [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_TwoThousandFourteenStockOptionMember_lbl" xml:lang="en-US" id="id_9891417_1863081_1_1">Two Thousand Fourteen Stock Option [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_TwoThousandFourteenStockOptionMember_lbl" xml:lang="en-US" id="id_9891417_1863081_2_1">2014 Stock Option and Incentive Plan [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_TwoThousandFourteenStockOptionMember" xlink:to="zfgn_TwoThousandFourteenStockOptionMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_TwoThousandSixStockOptionPlanMember" xlink:label="zfgn_TwoThousandSixStockOptionPlanMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_TwoThousandSixStockOptionPlanMember_lbl" xml:lang="en-US" id="id_9891417_1931050_3_1">Two Thousand Six Stock Option Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_TwoThousandSixStockOptionPlanMember_lbl" xml:lang="en-US" id="id_9891417_1931050_1_1">Two Thousand Six Stock Option Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_TwoThousandSixStockOptionPlanMember_lbl" xml:lang="en-US" id="id_9891417_1931050_2_1">2006 Stock Option Plan [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_TwoThousandSixStockOptionPlanMember" xlink:to="zfgn_TwoThousandSixStockOptionPlanMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="us-gaap_UnrecognizedTaxBenefits"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_UnrecognizedTaxBenefits_lbl" xml:lang="en-US" id="id_9891417_1645975_1_1">Unrecognized Tax Benefits</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_UnrecognizedTaxBenefits_lbl" xml:lang="en-US" id="id_9891417_1645975_2_1">Unrecognized tax benefits</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnrecognizedTaxBenefits" xlink:to="us-gaap_UnrecognizedTaxBenefits_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UseOfEstimates" xlink:label="us-gaap_UseOfEstimates"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_UseOfEstimates_lbl" xml:lang="en-US" id="id_9891417_1642359_1_1">Use of Estimates, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_UseOfEstimates_lbl" xml:lang="en-US" id="id_9891417_1642359_2_1">Use of Estimates</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UseOfEstimates" xlink:to="us-gaap_UseOfEstimates_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_UsGovernmentSecuritiesDueWithinOneYearMember" xlink:label="zfgn_UsGovernmentSecuritiesDueWithinOneYearMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_UsGovernmentSecuritiesDueWithinOneYearMember_lbl" xml:lang="en-US" id="id_9891417_1885455_3_1">Us Government Securities Due Within One Year [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_UsGovernmentSecuritiesDueWithinOneYearMember_lbl" xml:lang="en-US" id="id_9891417_1885455_1_1">Us Government Securities Due Within One Year [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="zfgn_UsGovernmentSecuritiesDueWithinOneYearMember_lbl" xml:lang="en-US" id="id_9891417_1885455_2_1">U.S. Government Securities (Due within 1 Year) [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="zfgn_UsGovernmentSecuritiesDueWithinOneYearMember" xlink:to="zfgn_UsGovernmentSecuritiesDueWithinOneYearMember_lbl"/>
    <loc xlink:type="locator" xlink:href="zfgn-20151231.xsd#zfgn_UsGovernmentSecuritiesMember" xlink:label="zfgn_UsGovernmentSecuritiesMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="zfgn_UsGovernmentSecuritiesMember_lbl" xml:lang="en-US" id="id_9891417_1702589_3_1">Us Government Securities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="zfgn_UsGovernmentSecuritiesMember_lbl" xml:lang="en-US" id="id_9891417_1702589_1_1">Us Government Securities [Member]</label>
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