<SEC-DOCUMENT>0001628280-25-002226.txt : 20250122
<SEC-HEADER>0001628280-25-002226.hdr.sgml : 20250122
<ACCEPTANCE-DATETIME>20250122172552
ACCESSION NUMBER:		0001628280-25-002226
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250121
FILED AS OF DATE:		20250122
DATE AS OF CHANGE:		20250122

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MOTT DAVID M
		CENTRAL INDEX KEY:			0001219871
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36485
		FILM NUMBER:		25546950

	MAIL ADDRESS:	
		STREET 1:		1119 ST. PAUL STREET
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21202

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ARDELYX, INC.
		CENTRAL INDEX KEY:			0001437402
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		34175 ARDENWOOD BLVD.
		CITY:			FREMONT
		STATE:			CA
		ZIP:			94555
		BUSINESS PHONE:		510-745-7047

	MAIL ADDRESS:	
		STREET 1:		34175 ARDENWOOD BLVD.
		CITY:			FREMONT
		STATE:			CA
		ZIP:			94555

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NTERYX INC
		DATE OF NAME CHANGE:	20080611
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1737584745.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-01-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001437402</issuerCik>
        <issuerName>ARDELYX, INC.</issuerName>
        <issuerTradingSymbol>ARDX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001219871</rptOwnerCik>
            <rptOwnerName>MOTT DAVID M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ARDELYX, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>400 FIFTH AVENUE, SUITE 210</rptOwnerStreet2>
            <rptOwnerCity>WALTHAM</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02451</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-01-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>199000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.9883</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1937765</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The Reporting Person holds 87,566 shares for the benefit of entities associated with New Enterprise Associates and disclaims beneficial ownership of such shares, except to the extent of his actual pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Elizabeth Grammer, Attorney-in-Fact for David Mott</signatureName>
        <signatureDate>2025-01-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
