- Clair Health, a San Francisco-based startup, has raised $11.6 million in seed funding led by Khosla Ventures. The company plans to launch the first noninvasive, continuous hormone monitor for women in November 2026.
- Clair’s device uses 10 biosensors and more than 130 biomarkers to track estrogen, progesterone, LH, and FSH in real time, all without blood draws or needles.
- Early testing has already identified nine unique sub-phases in the female hormone cycle, challenging the long-standing four-phase model used in women’s health.
Women were not required to be included in US clinical trials until 1993. Jenny Duan learned this as an undergraduate at Stanford, and it stuck with her.
That realisation led to Clair Health, a San Francisco startup that she co-founded with Abhinav Agarwal after they met at Stanford in the spring of 2025. The company, working on what it calls the first noninvasive, continuous hormone monitor for women, just closed $11.6 million in seed funding to bring the product to market.
The funding round was led by Khosla Ventures, the firm known for backing DoorDash, Affirm, and Okta, with participation from a16z speedrun, Brydge Club, Treehub, Cartan Capital, AGI House, Insiders VC, and Anne Wojcicki.
The $96 billion blind spot
The wearable market is now worth $96 billion, and 35% of women use a wearable device daily for fitness and wellness tracking. Despite all the research and development in this area, a basic problem remains unsolved.
WHOOP tracks HRV, Oura monitors sleep, and Fitbit counts steps, relying on the assumption that the body behaves the same way every day. For women, that’s not the case.
“What brands like Oura and Apple have found through R&D is impressive and necessary for monitoring, but an essential factor for females has been overlooked from the beginning, which is hormone health. These brands are adding women’s health features to their products rather than making them the blueprint,” explains Agarwal to Tech Funding News.
This gap appears in daily life. “A woman’s wearable might show her sleep and readiness scores are great, but internally, she feels off. This could be because the wearable doesn’t have the ability to track how her hormones, such as progesterone, are influencing her energy, and therefore, not providing her the clearest picture of her health,” he adds.
On top of that, about 30% of women have irregular cycles, so calendar-based predictions built on a standard 28-day model are almost useless for them. This shows just how big the oversight is.
Duan experienced this herself. She had irregular cycles and felt that existing cycle-tracking apps did not represent her. While studying AI ethics and social systems at Stanford, she realised that wearables were already collecting useful signals like heart rate, temperature, HRV, and electrodermal activity.
What was missing were algorithms that could interpret these signals through a hormonal perspective.
10 sensors, 130 biomarkers, and zero needles
Founded in 2025, Clair uses 10 biosensors and more than 130 proprietary biomarkers to continuously measure estrogen, progesterone, LH, and FSH, without blood draws, urine tests, or needles.
Instead of relying on a single metric, which can be affected by factors like stress or caffeine, the device collects signals from multiple sources simultaneously. Agarwal, who previously helped develop the world’s first noninvasive continuous glucose monitor at KOS AI, created the core algorithm with Duan.
Early results show 94.1% accuracy in classifying cycle phases, and an independent clinical trial at the Stanford Gladstone BeeHive program is underway, with plans for peer-reviewed publication.
WHOOP, Oura, and Fitbit have all added more women’s health features in recent years, but none of them uses hormone monitoring as a core feature. Flo Health, which raised $200 million at a valuation over $1 billion in July 2024, and Natural Cycles, the first FDA-cleared digital contraceptive app, both focus on cycle tracking but rely on calendar predictions and manual data entry rather than continuous physiological sensing.
What sets Clair apart is its hardware and algorithm stack, which were designed from the beginning with female biology in mind.
Creating a foundational hormonal data layer for women
Clair is entering the market just as big tech companies are starting to pay attention, but the main problem remains unsolved. The company’s 25,000-person waitlist, built months before launch, shows there is already strong consumer interest.
“For too long, women’s health has been an underserved category where women have been left to guess about what’s truly going on below the surface. We believe Clair will fundamentally change how women understand their bodies, and we’re proud to support the shift Jenny and Abhinav are creating,” says Emily Bennett, partner at a16z speedrun.
“Recent advances in sensors, combined with cross-modal learning approaches in AI, are unlocking Clair’s capabilities. As Clair continues to improve its AI models, the company will be able to provide more accurate insights into women’s health and physiology, with the overall goal of improving women’s healthspan and quality of life,” adds Alex Morgan, MD, PhD, partner at Khosla Ventures.
The fresh funding will support the wearable’s launch in November 2026 and ongoing clinical research, which is crucial in a field that remains underfunded and underresearched. Clair’s long-term goal is to create a foundational hormonal data layer for women, starting from their first period through perimenopause and beyond.
The company now hopes to show that continuous hormone data can transform women’s health the way continuous glucose monitors changed diabetes care, by shifting from reactive to preventative approaches.
