UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 14, 2026

Jaguar Health, Inc.

(Exact name of Registrant as Specified in Its Charter)

Registrant’s Telephone Number, Including Area Code: (415) 371-8300

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 3.03 Material Modification to Rights of Security Holders.

To the extent required by Item 3.03 of Form 8-K, the information regarding the Reverse Stock Split (as defined below) contained in Item 5.03 of this Current Report on Form 8-K is incorporated by reference herein.

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

As previously disclosed, at the special meeting of stockholders of Jaguar Health, Inc. (the “Company”) held on April 20, 2026 (the “Special Meeting”), the Company’s stockholders approved, among other things, an amendment (the “Twelfth Amendment”) to the Company’s Third Amended and Restated Certificate of Incorporation, as amended (the “COI”), to effect a reverse stock split of the Company’s issued and outstanding shares of common stock, par value $0.0001 per share (the “Common Stock”), at a ratio of not less than 1-for-15 and not greater than 1-for-150, with the exact ratio within that range to be determined at the discretion of the Company’s board of directors (the “Board”) on or before April 20, 2027.

Pursuant to such authority granted by the Company’s stockholders, the Board approved a one-for-fifteen (15) reverse stock split (the “Reverse Stock Split”) of the Common Stock, and on September 14, 2026, the Company filed the Twelfth Amendment with the Secretary of State of the State of Delaware. The Reverse Stock Split will become effective in accordance with the terms of the Twelfth Amendment at 12:01 am Eastern Time on September 17, 2026 (the “Effective Time”). When the Reverse Stock Split becomes effective, every fifteen (15) shares of the Company’s issued and outstanding Common Stock immediately prior to the Effective Time shall automatically be reclassified into one (1) share of Common Stock, without any change in the par value per share. The Reverse Stock Split reduces the number of shares of Common Stock issuable upon the exercise or vesting of its outstanding stock options and warrants in proportion to the ratio of the Reverse Stock Split and causes a proportionate increase in the conversion and exercise prices of such stock options and warrants. In addition, the number of shares reserved for issuance under the Company’s equity compensation plans immediately prior to the Effective Time will be reduced proportionately. The Reverse Stock Split did not change the total number of authorized shares of Common Stock or preferred stock of the Company.

No fractional shares will be issued as a result of the Reverse Stock Split. Stockholders who otherwise would be entitled to receive a fractional share in connection with the Reverse Stock Split will receive a cash payment in lieu thereof.

Equiniti Trust Company, LLC is acting as exchange agent for the Reverse Stock Split and will correspond with stockholders of record regarding the Reverse Stock Split. Stockholders who hold their shares in book-entry form or in “street name” (through a broker, bank or other holder of record) are not required to take any action.

Commencing on September 17, 2026, trading of the Company’s Common Stock will continue on The Nasdaq Capital Market on a Reverse Stock Split-adjusted basis. The new CUSIP number for the Company’s Common Stock following the Reverse Stock Split is 47010C 854.

The foregoing description of the Twelfth Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the Twelfth Amendment, which is filed as Exhibit 3.1 to this report and incorporated by reference herein.

Item 7.01 Regulation FD Disclosure.

On September 15, 2026, the Company issued a press release announcing the effectuation of the Reverse Stock Split, a copy of which is furnished as Exhibit 99.1.

The information in Exhibit 99.1 attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that Section, or incorporated by reference into any of the Company’s filings under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in any such filing.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.