Profusa, Inc.

As filed with the Securities and Exchange Commission on August 8, 2025.

Registration No. 333-________

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORMS-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

(Exact name of registrant as specified in its charter)

626 Bancroft Way

Suite A

Berkeley, CA 94710

(925) 997-6925

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Ben C. Hwang

Chief Executive Officer

626 Bancroft Way

Suite A

Berkeley, CA 94710

(925) 997-6925

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Ralph V. De Martino, Esq.

Marc Rivera, Esq.

ArentFox Schiff LLP

1717 K Street, NW

Washington, DC 20006

Phone: (202) 724-6847

Approximate date of commencement of proposed sale to the public: As soon as practicable after this registration statement becomes effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box:☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

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 7(a)(2)(B) of the Securities Act.☐

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this preliminary prospectus is not complete and may be changed. The selling shareholders may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell, nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED AUGUST 8, 2025.

PRELIMINARY PROSPECTUS

8,970,830 Shares of Common Stock by the Selling Stockholder

This prospectus relates to the offer and sale of up to 8,970,830 shares of our Common Stock, par value $0.0001 per share (“the Common Stock”), by Ascent Partners Fund LLC, whom we refer to in this prospectus as “Ascent” or the “Selling Stockholder.”

The shares of Common Stock to which this prospectus relates have been or may be issued by us to Ascent pursuant to a common stock purchase agreement, dated as of July 28, 2025, we entered into with Ascent, which we refer to in this prospectus as the Purchase Agreement. Such shares of Common Stock include up to 8,970,830 shares of Common Stock, consisting of (i) up to 8,070,830 shares of Common Stock (the “Purchase Shares”) that we may, in our sole discretion, elect to sell to Ascent, from time to time over a period of up to 36 months from and after the Effective Date (defined below) pursuant to the Purchase Agreement and (ii) 900,000 shares of Common Stock (the “Commitment Warrant Shares” and, together with the Purchase Shares, “ELOC Shares”) issuable upon exercise of the warrants we issued to Ascent upon our execution of the term sheet relating to the Purchase Agreement on July 20, 2025 (the “Commitment Warrants”), as consideration for its commitment to purchase shares of our Common Stock that we may, in our sole discretion, direct Ascent to purchase from us pursuant to the Purchase Agreement. The Commitment Warrants have an exercise price of $0.01 and may be exercised for cash or, if at the time of exercise there is no effective registration statement covering the resale of the Commitment Warrant Shares, on a cashless basis. If we do not require Ascent to purchase any Purchase Shares on or before the 100 th day following the execution of the Purchase Agreement, the number of Commitment Warrant Shares underlying the Commitment Warrants will be reduced to 450,000.

We are not selling any securities under this prospectus and will not receive any of the proceeds from the sale of our Common Stock by the Selling Stockholder. However, we may receive up to $100,000,000 in aggregate gross proceeds under the Purchase Agreement from sales of Common Stock we may elect to make to put to Ascent pursuant to the Purchase Agreement after the date of this prospectus. See“The Committed Equity Facility” for a description of the Purchase Agreement and“Selling Stockholder” for additional information regarding Ascent.

Ascent may sell or otherwise dispose of ELOC Shares described in this prospectus in a number of different ways and at varying prices. See“Plan of Distribution — Offer and Resale of Common Stock by the Selling Stockholder” for more information about how Ascent may sell or otherwise dispose of ELOC Shares pursuant to this prospectus. Ascent may be deemed to be an “underwriter” within the meaning of Section 2(a)(11) of the Securities Act of 1933, as amended, or the Securities Act.

The Selling Stockholder may sell the shares of our common stock offered by this prospectus from time to time on terms to be determined at the time of sale through ordinary brokerage transactions or through any other means described in this prospectus under the caption“Plan of Distribution.” The shares of common stock may be sold at fixed prices, at market prices prevailing at the time of sale, at prices related to prevailing market price or at negotiated prices.

We will pay the expenses incurred in registering under the Securities Act the offer and sale of the shares of Common Stock to which this prospectus relates by the Selling Stockholder, including legal and accounting fees. See“Plan of Distribution — Offer and Resale of Common Stock by the Selling Stockholder” beginning on page 148.

Our common stock is listed on the Nasdaq Global Market under the symbol “PFSA.” On August 5, 2025, the last sale price for our common stock as reported on the Nasdaq Global Market was $0.53 per share.

We are a “smaller reporting company” as defined under the federal securities laws and, as such, have elected to comply with certain reduced public company reporting requirements for this prospectus and may elect to do so in future filings.

Investing in our securities involves a high degree of risk. See the section entitled“Risk Factors” appearing on page 6 of this prospectus for a discussion of information that should be considered in connection with an investment in our securities.

Neither the Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is__________, 2025