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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2017-03-07</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001484565</issuerCik>
        <issuerName>Capnia, Inc.</issuerName>
        <issuerTradingSymbol>CAPN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001120443</rptOwnerCik>
            <rptOwnerName>TP MANAGEMENT VII LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 SHORELINE HWY, SUITE 282, BLDG B</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILL VALLEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94941</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001120461</rptOwnerCik>
            <rptOwnerName>TECHNOLOGY PARTNERS FUND VII LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 SHORELINE HWY, SUITE 282, BLDG B</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILL VALLEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94941</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001133704</rptOwnerCik>
            <rptOwnerName>TECHNOLOGY PARTNERS AFFILIATES VII LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 SHORELINE HWY, SUITE 282, BLDG B</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILL VALLEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94941</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>145766</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6827173</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person(s) acquired these securities on March 7, 2017, as consideration for the reporting person(s) common stock of Essentialis, Inc. (&quot;Essentialis&quot;), which was acquired by the Issuer, through a merger of a wholly-owned subsidiary of Issuer with and into Essentialis on March 7, 2017 pursuant to the Agreement and Plan of Merger dated December 22, 2016, by and between the Issuer, Merger Sub (as defined in the Merger Agreement), Essentialis and the Stockholders Representative (as defined therein) (the &quot;Merger Agreement&quot;).</footnote>
        <footnote id="F2">The reporting person(s) acquired these securities on March 7, 2017, as consideration for the reporting person(s) common stock of Essentialis, Inc. (&quot;Essentialis&quot;), which was acquired by the Issuer, through a merger of a wholly-owned subsidiary of Issuer with and into Essentialis on March 7, 2017 pursuant to the Agreement and Plan of Merger dated December 22, 2016, by and between the Issuer, Merger Sub (as defined in the Merger Agreement), Essentialis and the Stockholders Representative (as defined therein) (the &quot;Merger Agreement&quot;) and a related private placement closing concurrently with the merger transaction.</footnote>
        <footnote id="F3">The shares are held directly by Technology Partners Affiliates VII, L.P. (&quot;Affiliates VII&quot;). The Reporting Person is the sole general partner of Affiliates VII, and may be deemed to beneficially own such shares. The Reporting Person holds voting and dispositive power with respect to the securities held by Affiliates VII. James Glasheen, Sheila Mutter, Roger Quy, Ira Ehrenpreis, and Ted Ardell, and certain other individuals are members of the Reporting Person and disclaim beneficial ownership of the securities held by Affiliates VII except to the extent of any pecuniary interest therein.</footnote>
        <footnote id="F4">The shares are held directly by Technology Partners Fund VII, L.P. (&quot;Technology Partners VII&quot;). The Reporting Person is the sole general partner of Technology Partners VII, and may be deemed to beneficially own such shares. The Reporting Person holds voting and dispositive power with respect to the securities held by Technology Partners VII. James Glasheen, Sheila Mutter, Roger Quy, Ira Ehrenpreis, and Ted Ardell, and certain other individuals are members of the Reporting Person and disclaim beneficial ownership of the securities held by Technology Partners VII except to the extent of any pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/James Glasheen, as a Managing Member of TP Management VII, LLC</signatureName>
        <signatureDate>2017-03-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/James Glasheen, as a Managing Member of TP Management VII, LLC, the sole general partner of Technology Partners Fund VII, L.P.</signatureName>
        <signatureDate>2017-03-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/James Glasheen, as a Managing Member of TP Management VII, LLC, the sole general partner of Technology Partners Affiliates VII, L.P</signatureName>
        <signatureDate>2017-03-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
