<SEC-DOCUMENT>0001056358-17-000053.txt : 20170830
<SEC-HEADER>0001056358-17-000053.hdr.sgml : 20170830
<ACCEPTANCE-DATETIME>20170830184051
ACCESSION NUMBER:		0001056358-17-000053
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170829
FILED AS OF DATE:		20170830
DATE AS OF CHANGE:		20170830

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BALA ALFREDO
		CENTRAL INDEX KEY:			0001414010

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-24657
		FILM NUMBER:		171061706

	MAIL ADDRESS:	
		STREET 1:		28 CITY VIEW CIRCLE
		CITY:			NORTH PROVIDENCE
		STATE:			RI
		ZIP:			02911

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MANNATECH INC
		CENTRAL INDEX KEY:			0001056358
		STANDARD INDUSTRIAL CLASSIFICATION:	MEDICINAL CHEMICALS & BOTANICAL PRODUCTS [2833]
		IRS NUMBER:				752508900
		STATE OF INCORPORATION:			TX
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		600 SOUTH ROYAL LANE
		STREET 2:		SUITE 200
		CITY:			COPPELL
		STATE:			TX
		ZIP:			75019
		BUSINESS PHONE:		9724717400

	MAIL ADDRESS:	
		STREET 1:		600 SOUTH ROYAL LANE
		STREET 2:		SUITE 200
		CITY:			COPPELL
		STATE:			TX
		ZIP:			75019
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_150413283759421.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-08-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001056358</issuerCik>
        <issuerName>MANNATECH INC</issuerName>
        <issuerTradingSymbol>MTEX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001414010</rptOwnerCik>
            <rptOwnerName>BALA ALFREDO</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>600 S. ROYAL LANE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>COPPELL</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO and President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.0001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2017-08-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>550</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.85</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9480</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in Column 4 is a weighted average price. These shares were sold in two transactions. The prices for both transactions were $14.85. The reporting person undertakes to provide Mannatech, Incorporated, any security holder of Mannatech, Incorporated, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this Form 4.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/S/ David Johnson, Chief Financial Officer by Power of Attorney</signatureName>
        <signatureDate>2017-08-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
