Amendment: SEC Form SCHEDULE 13G/A filed by Surrozen Inc.

The address of the principal business office of each of the Reporting Persons is: c/o RA Capital Management, L.P., 200 Berkeley Street, 18th Floor, Boston MA 02116

RA Capital and the Fund are Delaware limited partnerships. Dr. Kolchinsky and Mr. Shah are United States citizens.

Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of shares of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2025 and is incorporated by reference. The Fund directly holds (i) 679,130 shares of Common Stock, (ii) pre-funded warrants (the "Pre-Funded Warrants") exercisable for up to 40,000 shares of Common Stock, (iii) Series A warrants (the "Series A Common Warrants") exercisable for up to 322,580 shares of Common Stock, (iv) Series B warrants (the "Series B Common Warrants") exercisable for up to 350,876 shares of Common Stock, and (iv) Series E warrants (the "Series E Common Warrants" and, together with the Pre-Funded Warrants, Series A Common Warrants and Series B Common Warrants, the "Warrants") exercisable for up to 198,275 shares of Common Stock. Each of the Warrants contains a provision (the "Beneficial Ownership Blockers") which precludes exercise of the Warrants to the extent that, following exercise, the Fund, together with its affiliates and other attribution parties, would own more than 9.99% of the Common Stock outstanding. The Fund is currently prohibited from exercising the Warrants to the extent that such exercise would result in the Reporting Persons' beneficial ownership of more than 867,418 shares of Common Stock. RA Capital Healthcare Fund GP, LLC is the general partner of the Fund. The general partner of RA Capital is RA Capital Management GP, LLC, of which Dr. Kolchinsky and Mr. Shah are the controlling persons. RA Capital serves as investment adviser for the Fund and may be deemed a beneficial owner, for purposes of Section 13(d) of the Act, of any securities of the Issuer held by the Fund. The Fund has delegated to RA Capital the sole power to vote and the sole power to dispose of all securities held in the Fund's portfolio, including the shares of the Issuer's Common Stock reported herein. Because the Fund has divested voting and investment power over the reported securities it holds and may not revoke that delegation on less than 61 days' notice, the Fund disclaims beneficial ownership of the securities it holds for purposes of Section 13(d) of the Act. As managers of RA Capital, Dr. Kolchinsky and Mr. Shah may be deemed beneficial owners, for purposes of Section 13(d) of the Act, of any securities of the Issuer beneficially owned by RA Capital. RA Capital, Dr. Kolchinsky, and Mr. Shah disclaim beneficial ownership of the securities reported in this Schedule 13G other than for the purpose of determining their obligations under Section 13(d) of the Act, and the filing of this Schedule 13G shall not be deemed an admission that either RA Capital, Dr. Kolchinsky, or Mr. Shah is the beneficial owner of such securities for any other purpose.

Due to the Beneficial Ownership Blockers listed in the Warrants, each Reporting Person's beneficial ownership percentage was 9.99% as of March 31, 2025. Such percentage is based upon the sum of (i) 8,494,584 shares of the Issuer's Common Stock outstanding as of March 31, 2025, as reported in the Issuer's Registration Statement on Form S-3 filed with the Securities and Exchange Commission (the "SEC") on April 23, 2025 and (ii) 188,288 shares of Common Stock issuable upon the exercise of the Warrants. Due to field limitations of the EDGAR filing system, the percentages listed in Row 11 of the Reporting Persons' cover pages have been rounded down to 9.9%.

Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2025 and is incorporated by reference.

Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2025 and is incorporated by reference.

Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2025 and is incorporated by reference.

Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2025 and is incorporated by reference.