Tiny Health, an Austin, Texas-based microbiome testing and health intelligence company, has raised $33 million in a Series B funding round led by B Capital. Existing investors Spero Ventures, The Venture City and Overwater Ventures participated alongside new investors Black Opal Ventures, Denver Ventures, Pave Health Ventures, Alumni Ventures, Gaingels and Pari Passu Ventures. The round brings Tiny Health’s total funding to $46 million.
Founded in 2020 by Cheryl Sew Hoy, Tiny Health initially focused on microbiome testing for mothers and babies before expanding its testing platform across different life stages. Donald Koo joined the company as co-founder following its 2022 product launch.
Tiny Health provides gut and vaginal microbiome testing using shotgun metagenomic sequencing. Its platform serves nearly 200,000 customers and more than 6,000 healthcare practitioners across independent practices, hospital systems, longevity clinics and precision medicine organisations.
The company plans to use the Series B funding to advance clinical research and interventional studies, expand education for healthcare practitioners and scale Powered by Tiny, its B2B platform. Tiny Health is also developing TinyAI, which the company says is trained on its proprietary dataset of nearly 200,000 microbiome profiles to provide personalised guidance linked to users’ results.
Alongside the financing, Tiny Health announced a $5 million Microbiome Research Program intended to give researchers, clinicians and scientific partners access to its testing, data and research capabilities. The company said the initiative will support research into microbiome-related interventions and help generate additional clinical evidence.
In September 2025, researchers affiliated with Tiny Health published an open-label randomised controlled trial involving 54 C-section-born infants in Pediatric Allergy and Immunology. The study reported lower prevalence of atopic dermatitis in the intervention group, with an odds ratio of 0.17 compared with the control group.
Tiny Health previously raised an $8.5 million Series A led by Spero Ventures, which brought its total funding at the time to $13 million.
