Funding profile · Infant microbiome

Persephone Biosciences

Nine years old, one Form D on file, and it is for $317,000 of options sold in 2021. The $15 million seed the company announced in 2022 left no notice on EDGAR at all. What the record does show is a research program that has outrun its funding and a consumer product now carrying the company.

$15.0MSeed round announced July 2022, company-reported
$317KTotal sold across every Form D on file, all of it in 2021
24Investors in that filing, about $13,200 each
1.5MDoses of Bloom and Thrive manufactured in year one, company-reported

Data as of September 22, 2026. Company-reported figures are labeled.

Rounds at a glance

When Round Amount Investors Source
2018 Y Combinator, Winter 2018 batch Not disclosed Y Combinator YC data
Feb to Mar 2021 Option offering, Rule 506(b) $317,000 sold of $317,000 offered 24 investors, $10,000 minimum Form D
Jul 2022 Seed $15,000,000 announced Co-led by First Bight Ventures and Propel Bio Partners, with Y Combinator, Fifty Years, Susa Ventures, American Cancer Society BrightEdge Fund, Pioneer Fund, ZhenFund Release, confirmed by SDBJ
2024 to 2026 No round announced Not disclosed Named investor list adds Ocampo Capital, Mesa Verde Partners, Capita3; ZhenFund drops off Company-stated
2017 to 2026 Federal grants None found No NIH RePORTER or NSF award records located Not found

What the filings show

Persephone Biosciences, Inc. · Form D · filed Mar 4, 2021

First sale
Feb 19, 2021
Security type
Option to acquire equity
Offered
$317,000
Sold
$317,000 · $0 remaining
Investors
24 · average about $13,208 · $10,000 minimum
Exemption
Rule 506(b), no non-accredited investors
Sales compensation
None · finders fees $0
Related persons
Stephanie Culler (executive officer, director); Stephen Van Dien (executive officer, director)
Issuer detail
Delaware corporation, incorporated 2017 · San Diego, CA · revenue range: decline to disclose
Filing
SEC EDGAR, CIK 0001848850

Reading the filings

  1. The SEC file is close to empty.A full text search of Form D filings for the company name returns one document in nine years. It reports $317,000 sold to 24 investors, an average of about $13,208 each against a $10,000 minimum. That is 2.1 percent of the $15 million the company announced sixteen months later.
  2. The one filing is options, not preferred stock.The security box is marked as an option to acquire equity. Twenty four holders at roughly thirteen thousand dollars apiece is the shape of an employee and advisor pool or a small friends round, not an institutional preferred financing.
  3. It was filed on time, then nothing.First sale February 19, 2021; filed March 4, thirteen days later, inside the fifteen day Regulation D window. So the company knows how to file. The absence since means later money either came in under Section 4(a)(2), which requires no notice, or it did not come in.
  4. The investor list grew without a round attached.The 2022 release named eight backers. The 2025 and 2026 boilerplate names ten, adding Ocampo Capital, Mesa Verde Partners and Capita3, and quietly dropping ZhenFund. Ocampo Capital described advising on retail go to market in an October 2024 interview. No amount, date or instrument was published for any of it.
  5. The research side shows the strain.ARGONAUT, the 5,000 patient oncology study the seed round was explicitly raised to fund, sits suspended on ClinicalTrials.gov. The reason field, last updated September 15, 2026, reads “Currently no funding to continue study.” VOICES was terminated at 15 subjects against a planned 10,000. That is a company choosing where to spend, in public.
  6. Governance moved without a filing to mark it.The 2021 Form D lists only the two founders as related persons. The website now shows a six member board including Daniel Bradbury as chairman, Paul Grint, Veronique Riethuisen, and partners from both seed co-leads: Leen Kawas of Propel Bio Partners and Veronica Breckenridge of First Bight Ventures. Investor directors normally arrive with a priced round. No filing records one.

Commercial signals

Signal Detail Source type
Regulatory Bloom and Thrive are dietary supplements. No FDA approval, 510(k) or PMA record, and none required for this class. Public record
Price $74.95 list, $64.95 on subscription, for a 30 day supply. Company site
Channels Direct to consumer from Sep 9, 2025. Amazon from Jun 23, 2026. Big box retail stated as next. Company-stated
Traction 10,000 waitlist sign ups pre launch; more than 1.5 million doses manufactured in year one; thousands of children. No revenue, unit sales or subscriber figure published. Company-stated
Clinical evidence Three peer reviewed papers since June 2025. The ARTEMIS trial was funded by Persephone and every author was employed by or held stock in it. Public record
Certification Clean Label Project. The 2025 release and product page cite the First 1,000 Days Promise; the September 2026 release cites the Purity Award. Certifier-stated

What to watch

  • A Form D for anything raised after February 2021. It would be the first hard number since the seed announcement.
  • Whether ARGONAUT resumes, is withdrawn, or stays suspended for lack of funding.
  • Any revenue or subscriber disclosure. Doses manufactured is a production figure, not a sales figure.
  • Big box retail placement, the stated next commercial step and the one that would need working capital.
  • A registered trial with a health outcome as the primary endpoint, which is what the product claims rest on.

The Persephone Biosciences story on Healthcare DiscoveryHealthcare Discovery

Related companies

  • Avro Life Science: Shared investor: Susa Ventures. Two University of Waterloo first years set out to put a generic allergy pill into a sticker
  • Pine Park Health: Shared investor: Susa Ventures. A primary care practice that puts clinicians inside senior living communities instead of asking residents to travel out
  • Nourish: Shared investor: Susa Ventures. A telehealth company that bills health insurance for visits with registered dietitians
  • Osmind: Shared investor: Susa Ventures. An electronic health record for psychiatry practices delivering ketamine, esketamine and TMS, and a real world evidence business built on what those practices record

Sources

  1. Public recordForm D, Persephone Biosciences, Inc., CIK 0001848850SEC EDGAR · Mar 4, 2021
  2. Public recordEDGAR full text search, Form D filings naming Persephone BiosciencesSEC · accessed Sep 22, 2026
  3. Public recordClinicalTrials.gov NCT04638751, ARGONAUT, and NCT04770649, VOICESClinicalTrials.gov · updated Sep 15, 2026 and Apr 3, 2024
  4. Public recordClinicalTrials.gov NCT06746285, ARTEMISClinicalTrials.gov · updated Aug 21, 2026
  5. Public recordSafety, tolerability, and gastrointestinal effect of a Bifidobacterium-based synergistic synbiotic in infants and toddlersPediatric Research · Aug 12, 2026
  6. IndependentPersephone Lands $15M Seed for Microbiome PlatformSan Diego Business Journal · Aug 12, 2022
  7. InterviewNewsletter 11: An Interview with a Persephone Biosciences Co-FounderOcampo Capital · Oct 20, 2024
  8. IndependentNew synbiotic targets missing gut microbes in US babiesNutraIngredients · Sep 26, 2025
  9. CompanyPersephone Biosciences Closes $15M Seed Financing RoundBusiness Wire · Jul 19, 2022
  10. CompanyPersephone Biosciences Celebrates First Birthday of Bloom and Thrive SynbioticsGlobeNewswire · Sep 9, 2026
  11. CompanyPersephone Biosciences website, team and Bloom product pagespersephone.bio · accessed Sep 22, 2026

Compiled from SEC, ClinicalTrials.gov and FDA public records and published reports as of September 22, 2026. Form D notices report offerings under Regulation D; amounts reflect the filing date and may not capture later sales. Offerings made under Section 4(a)(2) require no Form D, so an absent filing is not proof that no capital was raised. Healthcare Venture Capital Fund holds no position in Persephone Biosciences. This page is not an offer to sell or a recommendation to buy any security.