Tiny Health's gut-data bet pulls in $33M Series B led by B Capital

Tiny Health, the Austin-based company behind at-home microbiome tests, has raised $33 million in a Series B round led by B Capital, it told Crunchbase News exclusively.

The financing brings Tiny Health's total funding to $46 million. That figure follows a $4.5 million seed round in 2021 and an $8.5 million Series A in late 2023. Existing investors Spero Ventures, The Venture City and Overwater Ventures participated in the latest round, along with new investors including Black Opal Ventures and Alumni Ventures. The company said the money will help it meet growing demand for its at-home microbiome tests.

The company's origin story is a family one. When founder and CEO Cheryl Sew Hoy's daughter developed eczema, allergies and food sensitivities, Sew Hoy began reading research on the infant gut microbiome. Her daughter had been born by C-section, while her younger son, born vaginally, had no similar conditions. The contrast made her wonder whether differences in their early microbial exposure played a role. While it did not give her a diagnosis for her daughter, it gave her an idea for a company.

"I learned that you can course-correct if you focus on the early life of the baby. If they're missing certain beneficial bacteria, it can really cause a lot of issues for the infant," Sew Hoy recalled of her reading. "I was reading all this literature and asked my doctors about it, and none of my doctors knew what I was talking about."

A week after her son's birth in 2020, she incorporated the business.

That disconnect — between the microbiome literature Sew Hoy was working through on her own and what her own physicians could tell her — is essentially the opening Tiny Health is now funded to pursue. The Series B is framed around exploring what gut data can reveal about future health, a question the company approaches from the earliest stage of life, when, in Sew Hoy's telling, imbalances in beneficial bacteria can set off problems for an infant.

For B Capital, the bet is on a consumer-facing testing business operating at the intersection of infant health and microbiome science, a category that has drawn increasing attention as sequencing costs fall and parents look for earlier explanations for conditions like eczema and food sensitivities. Tiny Health's pitch rests less on one-time test results than on the idea that early-life microbial data can inform decisions made long before symptoms become chronic.

Whether that thesis holds up at scale is the question the new capital is meant to answer. For now, the company has roughly $46 million in total backing and a lead investor in B Capital that is willing to fund the next phase of the argument.