<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-04-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001165320</issuerCik>
        <issuerName>Growblox Sciences, Inc.</issuerName>
        <issuerTradingSymbol>GBLX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001531964</rptOwnerCik>
            <rptOwnerName>Lazarus Management Co LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3200 CHERRY CREEK SOUTH DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 670</rptOwnerStreet2>
            <rptOwnerCity>DENVER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80209</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001232118</rptOwnerCik>
            <rptOwnerName>LAZARUS INVESTMENT PARTNERS LLLP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3200 CHERRY CREEK SOUTH DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 670</rptOwnerStreet2>
            <rptOwnerCity>DENVER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80209</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001531960</rptOwnerCik>
            <rptOwnerName>BORUS JUSTIN B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3200 CHERRY CREEK SOUTH DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 670</rptOwnerStreet2>
            <rptOwnerCity>DENVER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80209</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001539956</rptOwnerCik>
            <rptOwnerName>Lazarus Israel Opportunities Fund LLLP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3200 CHERRY CREEK SOUTH DRIVE, SUITE 670</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DENVER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80209</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Warrant (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2015-04-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.01</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2014-05-29</value>
            </exerciseDate>
            <expirationDate>
                <value>2019-05-29</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3000000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Warrant (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2015-04-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1000000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.01</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2014-06-02</value>
            </exerciseDate>
            <expirationDate>
                <value>2019-06-02</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1000000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The reported transactions involve the repurchase by the Issuer of warrants at a purchase price of $0.01 per warrant share.</footnote>
        <footnote id="F2">This form is filed jointly by Lazarus Management Company LLC (&quot;Lazarus Management&quot;), Justin B. Borus, Lazarus Investment Partners LLLP (&quot;Lazarus Partners&quot;) and Lazarus Israel Opportunities Fund LLLP (&quot;Lazarus Israel&quot; and together with Lazarus Partners, the &quot;Funds&quot;).  The securities reported herein were owned directly by Lazarus Partners (warrants to purchase 3,000,000 shares) and Lazarus Israel (warrants to purchase 1,000,000 shares).  Lazarus Management is the investment adviser and general partner of Lazarus Partners and Mr. Borus is the managing member of Lazarus Management.</footnote>
        <footnote id="F3">Each of Lazarus Management and Mr. Borus expressly disclaims beneficial ownership of the securities held by the Funds, in each case, except to the extent of his or its pecuniary interest therein. Each of the Funds expressly disclaims beneficial ownership of the shares held by the other Fund.  The filing of this Form 4 shall not be construed as an admission that either Lazarus Management or Mr. Borus, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, are the beneficial owner of any of the securities reported herein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Lazarus Management Company LLC By: /s/ Justin B. Borus, managing member</signatureName>
        <signatureDate>2015-04-29</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Justin B. Borus</signatureName>
        <signatureDate>2015-04-29</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Lazarus Investment Partners LLLP By: Lazarus Management Company LLC, its general partner By: /s/ Justin B. Borus, managing member</signatureName>
        <signatureDate>2015-04-29</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Lazarus Israel Opportunities Fund LLLP By: Lazarus Management Company LLC, its general partner By: /s/ Justin B. Borus, managing member</signatureName>
        <signatureDate>2015-04-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
