US startup builds wearable hormone tracker

Stanford graduates’ startup Clair is building a wearable hormone tracker for women, offering continuous, non-invasive monitoring.

The company, Clair, founded by Jenny Duan and Abhinav Agarwal, aims to build what its founders describe as a research-led, privacy-focused tool to help women see how hormone levels affect daily life.

Duan and Agarwal met in spring 2025 and began working on Clair shortly after. Over the past six months, they have been developing the technology and refining the company’s mission.

The device is designed to address gaps in women’s healthcare. Women remain underrepresented in medical research and clinical trials, leading to limited data and slower progress in understanding women’s health conditions.

According to Clair advisor and Stanford Medicine professor Brindha Bavan, hormone tracking in reproductive healthcare “improves our understanding of the function of and communication between the brain’s pituitary gland and ovaries or testes.

The pituitary gland is a small organ at the base of the brain that produces hormones regulating many bodily functions. The ovaries and testes are the primary reproductive organs that also produce sex hormones.

Hormonal health affects not only fertility and reproduction but also mental health, metabolism, energy levels and overall wellbeing.

Bavan said hormone tracking can “provide insight into menstrual cycle patterns and can aid with both diagnosing and assessing treatment for [various] conditions.”

“[Clair enables] patients [to] gain insight into their personal hormone fluctuations over different time periods,” Bavan said, “and share this information at healthcare visits to better understand and correlate any medical issues they are facing and avoid repeat blood draws.”

The device, which resembles a bracelet worn on the wrist, will connect to a mobile app, allowing all data processing to occur directly on the user’s phone rather than in external data centres.

“The device connects with an app so all of the processing happens on the app itself, not in a data centre like other devices. This is especially important given the current political climate around data privacy,” Agarwal said.

Clair also plans to pursue FDA approval and position itself as a medically credible device rather than solely a lifestyle product. The company is planning to launch a clinical trial at Stanford Medicine this spring.

Duan’s interest in women’s health and technology began as a Stanford undergraduate. At TreeHacks in 2024, she built apps focused on endometriosis, a condition where tissue similar to the lining of the womb grows outside of it.

She said a course on Philanthropy for Sustainable Development was particularly influential. “It was this class that sparked my interest in building a solution in [the women’s healthcare] space,” Duan said.