B Capital led a $33M Series B for Tiny Health, a round that lifts the Austin startup’s lifetime funding to $46M.
At-home microbiome testing is the product. Founder Cheryl Sew Hoy built the company after her daughter came down with eczema and allergies while a younger son, delivered vaginally, did not. Hunting for research on the infant gut, Sew Hoy discovered that her own doctors had little to offer.
A small stool sample, collected on a swab, is what customers send in; back comes a report on the microbes found, with explanations attached and next steps suggested. The sequencing method, shotgun metagenomics, casts a far wider net over microbial DNA than a test built around a fixed list of organisms.
Clinicians are where growth is fastest. The Powered by Tiny arm sells testing through providers and other companies, and it quadrupled over the past year to reach more than 6,000 practitioners. Mayo Clinic’s executive health program, Superpower and Fullscript all count as partners. Revenue has more than doubled every year, and nearly 200,000 samples have been collected.
Sew Hoy keeps the claims modest. Tiny Health is a wellness product in her telling, not a diagnostic: a sample reveals which microbes are present, but not what made a patient sick. No insurer pays for it.
Clinician training and TinyAI, a tool that reads results against the company’s research library, are what the fresh capital covers. Backers from earlier rounds, among them Spero Ventures, The Venture City and Overwater Ventures, returned. Black Opal Ventures and Alumni Ventures joined as new investors, and B Capital’s Nick Whitehead takes a board seat.
