Tiny Health Secures $33M to Study Microbiome and Future Wellness

When Cheryl Sew Hoy’s daughter developed food sensitivities, allergies, and eczema, she began researching the infant gut microbiome. Because her daughter was born via C-section while her younger son, delivered vaginally, experienced no such conditions, she questioned if early microbial exposure played a role. While the literature did not yield a diagnosis for her daughter, it sparked the concept for a business.

“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 explains. “I was reading all this literature and asked my doctors about it, and none of my doctors knew what I was talking about.”

One week after her son was born in 2020, she founded Austin-based Tiny Health. The company recently announced a $33 million Series B funding round led exclusively by B Capital, as shared with Crunchbase News.

This latest investment brings Tiny Health’s overall funding to $46 million, following a $4.5 million seed round in 2021 and an $8.5 million Series A in late 2023. Returning participants included Spero Ventures, The Venture City, and Overwater Ventures, alongside new backers Black Opal Ventures and Alumni Ventures. B Capital’s Nick Whitehead will also join the startup’s board of directors.

Interest in Tiny Health’s at-home microbiome testing kits continues to climb. Sew Hoy notes that overall revenue has more than doubled annually, while Powered by Tiny—its B2B division that distributes tests via healthcare professionals and corporate partners—grew fourfold over the past year. While declining to share specific valuation or revenue figures, Sew Hoy stated that the valuation sits significantly higher than during the Series A round.

From baby gut tests to adult testing

Before releasing its initial at-home baby gut test in 2022, Tiny Health spent two years building its platform. Healthcare was uncharted territory for Sew Hoy, whose previous venture, digital coupon platform Reclip.It, was acquired by Walmart Labs in 2013. Prior to securing seed funding, she invested $50,000 of her own capital into a pilot study, spending roughly a year gathering stool samples and constructing the infrastructure.

The infant test served as a targeted starting point. Sew Hoy observed that parents of children dealing with issues like eczema sought answers, whereas clinicians lacked practical ways to leverage emerging microbiome insights. Although the company ultimately expanded to include adult, pregnancy, and vaginal microbiome tests, infant testing drove its early days. Adults now comprise its largest testing demographic.

The testing process involves collecting a small stool sample using a swab. Once mailed in, customers receive an analysis of the microbes identified, paired with educational breakdowns and actionable recommendations. Tiny Health also provides a recurring subscription named Tiny Plus, which pairs an initial baseline test with a follow-up retest.

According to Sew Hoy, a primary differentiator for Tiny Health is its reliance on shotgun metagenomic sequencing to evaluate microbial DNA. This technique delivers a more comprehensive overview of sample organisms than methods searching for a restricted subset of microbes. Chief science officer Kimberley Sukhum, who joined in 2021, directs the scientific operations. Additional leadership includes co-founder Donald Koo—who joined two years after launch to oversee technology—and chief medical officer Dr. Elisa Song, an integrative pediatrician and former adviser.

Reports break down potential microbe functions and outline guidance like dietary adjustments, complete with links to relevant studies.

“We are a wellness test,” Sew Hoy stated. “We’re not a diagnostic … It’s very actionable, very evidence-backed.”

Insurance providers do not cover the tests, which pinpoint microbes present in a sample but cannot determine the underlying origin of a user’s symptoms.

Alternative approaches are emerging across the digestive health sector. Austin-based Throne Science offers a toilet-mounted attachment that monitors hydration and stool patterns, whereas Tiny Health evaluates microbial DNA from physical samples. Throne recently secured a $10 million Series A round led by Will Ventures.

Beyond direct-to-consumer testing

Powered by Tiny represents the enterprise division and fastest-growing segment of the business, supplying tests to medical providers and third-party companies integrating them into existing platforms. Current partners feature Mayo Clinic’s Executive Health and Longevity Programs, Fullscript, and Superpower, alongside academic groups and supplement brands measuring the microbiome for clinical research.

After direct-to-consumer customers began sharing reports with their physicians, clinicians started reaching out to Tiny Health for interpretation assistance, according to Sew Hoy. Today, the enterprise partners with over 6,000 practitioners, providing educational training on incorporating tests into patient care.

Scaling both direct-to-consumer lines and clinician training remains a focal point for the newly acquired capital.

Nick Whitehead, senior principal at B Capital, remarked that his firm sees strong potential in making microbiome science actionable for everyday consumers amid rising demand for preventative care.

“We’re in the middle of a real shift in how people engage with their own health. Consumers are paying out of pocket for wearables, blood panels, and full-body scans because they want to understand what’s happening inside their bodies before something goes wrong,” he wrote via email. “The gut microbiome is one of the most important and least understood pieces of that picture … Tiny Health turns that science into something people can actually act on, and we believe the company that does this well will define the category.”

Whitehead also noted that clinicians consulted during their due diligence consistently rated Tiny Health as the top-performing test.

Another major asset, Whitehead added, is the longitudinal data the company has built by tracking families starting from infancy.

Putting its data to work

Tiny Health has amassed nearly 200,000 microbiome samples over time, per Sew Hoy. To leverage this database, the startup is building a system named TinyAI, which will combine internal data with expert-vetted research to help users interpret their personal metrics. De-identified health information supplied by customers also contributes to this initiative.

Over the long term, Tiny Health aims to detect patterns that could signal health risks prior to disease onset. Published research links gut microbiome imbalances to more than 100 distinct conditions.

“We want to be able to predict disease before it happens and intervene before it happens,” Sew Hoy noted in her interview with Crunchbase News.

A central objective is evaluating whether microbiome-focused interventions can genuinely improve health outcomes. Tiny Health reports having published four scientific papers, including an infant-focused study, with plans to support future adult research.

Operating with a team of roughly 40 workers, the company intends to hire 30 additional staff members. The new funds will support scaling healthcare partnerships, fueling research on health outcomes, and allocating $5 million toward a program that grants clinical partners and researchers access to its data and testing infrastructure.

Related Crunchbase query:

• Global Venture Funding To Gut Microbiome-Related Startups In 2026

Related reading:

• Pooptech Startups Are Passing The Smell Test
• Investments In Poop Startups Are Piling Up

Illustration: Dom Guzman

Frequently Asked Questions

• How much funding has Tiny Health raised in total? Tiny Health has raised a total of $46 million, including a recent $33 million Series B round, an $8.5 million Series A in late 2023, and a $4.5 million seed round in 2021.
• What technology does Tiny Health use to analyze samples? The company uses shotgun metagenomic sequencing to analyze microbial DNA from collected stool samples.
• Are Tiny Health tests covered by health insurance? No, health insurance does not cover the tests.
• What is Powered by Tiny? Powered by Tiny is the company’s B2B arm that distributes tests through healthcare providers, supplement makers, and other corporate partners.
• Does Tiny Health provide medical diagnostics? No, Tiny Health classifies its offerings as wellness tests rather than diagnostic tools.