Stanford grads raise $11M to build noninvasive wearable for continuous hormone tracking

Two Stanford grads raise $11M to build a noninvasive wearable for hormone tracking

Stanford graduates Jenny Duan and Abhinav Agarwal want to solve two hard problems: create a good-looking wearable and measure hormones to help women understand their health better. The pair is building a startup called Clair Health to track inflammation and bloating markers, energy levels, and cycle phase classification to give insights into cycle irregularities and perimenopause as well as hormonal fluctuations and how to navigate those changes. The company has raised $11.6 million in a funding round led by Khosla Ventures, with participation from startup accelerator program a16z speedrun, Brydge Club, Treehub, Cartan Capital, AGI House, Insiders VC, Anne Wojcicki, and Stephanie Coleman. The startup said that, in order to collect more data specific to each user, it uses voice-based onboarding to understand their health markers. What's more, the company claims it has trained its own AI to analyze voice-based biomarkers and determine which phase of their cycle a user is in after just a few minutes of conversation. "What we found is that in women's health and in the current state of apps, women can't communicate a large amount of symptoms because the apps are built for only specific ones. With our voice stack, we are giving our users a way to communicate their own problems in their own way," Duan said. Through its wearable, Clair Health said it's able to determine what is causing hormones to change and how the body responds to those changes by evaluating the biomarkers picked up by its sensors. It also continuously monitors changes through the four phases of a menstruation cycle and doesn't just rely on the day of menstruation. Through these markers, the app shows information about the pace of aging, inflammation and bloating, and the rate of perceived exertion. Clair Health also wants to help women seeking care for menopause and perimenopause by providing more data to share with healthcare providers, allowing them to receive better support rather than orally recounting their symptoms. Duan said that became interested in women's health while working at a nonprofit in Portland, Oregon, during school. Later, she took a class at Stanford focused women's health and nonprofits, and during that time, she met Agarwal. The startup argues that typical health tracking devices like Apple Watch or a Pixel Watch rely on sensors like a gyroscope, an optical/PPG sensor, and a temperature sensor, which are not enough to track hormonal health. Clair Health's device has 10 biosensors, including a novel biomagnetic sensor for hormonal insights. "Until today, there hasn't been a single device, be it invasive or noninvasive, that can capture insights into hormones in real time and get to the source of a problem. We didn't start by thinking of building a particular piece of hardware. We just wanted to track hormones continuously," Duan told TechCrunch. The company said that it is building its own model based on different biomarkers for women's health, with data partnerships with access to several million electronic health records and longitudinal health data. Through its data partnerships, it wants to create insights into different issues, including endometriosis, PMDD (Premenstrual Dysphoric Disorder), perimenopause, and more. The startup is currently testing its device with a closed group of beta users and plans to ship units in November at a price point of $369 paired with a $9.99 monthly subscription. Users can place pre-orders for the device now. Mary Minno, an investor at Treehub, a Stanford-adjacent residency backed by the AI Health Fund, said that Clair Health is solving the problem of giving women actionable insight into their hormonal health. "Users want a product that does what it says it is going to do. Hormonal health measurement today is still archaic -- my perimenopausal friends are still getting blood draws to understand the efficacy of hormone treatments. Out of the gate, Clair aims to deliver a product that shines a light on what previously required a blood draw," Minno told TechCrunch via email. Startups are trying many approaches to measure hormone health. For instance, Level Zero Health focuses on continuous tracking through glucose monitor-style devices, while Hormona relies on home tests. Then there are apps like Ourself Health that rely on AI to provide insights based on manual logging done by users.

Exclusive: A 21-year-old Stanford grad just raised $11 million to put a hormone lab on your wrist | Fortune

Jenny Duan closed her seed round the same week she picked up her diploma. Duan, 21, graduated from Stanford University last weekend with a BS in Symbolic systems. She also closed an $11 million seed round for Clair Health, Fortune learned exclusively. Khosla Ventures led the round, with support from a16z Speedrun, Brydge Club, Treehub, Cartan Capital, AGI House, Insiders VC, and Anne Wojcicki. The startup, co-founded with Abhinav Agarwal, is building what it calls the first continuous, non-invasive hormone monitor for women. Instead of drawing blood or piercing skin, Clair Health's wearable wristband uses a stack of 10 biosensors -- including biomagnetic sensors it says are not found in any competing consumer wearable -- to read physiological signals like skin temperature, heart rate variability, and electrodermal activity, then runs those markers through AI models to infer where a woman is in her hormonal cycle. "Right now, to measure hormones, you either do a blood test in a lab or you pee on a stick at home," Duan told Fortune. "Any urine test is also not looking at hormones directly -- they're looking at how your body metabolizes them." Clair's AI correctly identified which phase of the menstrual cycle a woman was in 94% of the time, benchmarked against daily urine samples -- the same standard as at-home ovulation strips, not a clinical blood analysis. Independent third-party studies, including one through Stanford, are underway and will eventually put harder numbers on the table. Other wearable tech companies have been circling this space. Whoop launched women's hormonal insights in 2025 and expanded it with a women's-specific blood testing panel this Spring. Smart ring maker Oura launched a proprietary AI model for women's health in February 2026. And Natural Cycles already powers FDA-cleared birth control through Oura's temperature sensor. None of it was built from the ground up for hormones though. "Much of wearable technology being developed is bro-tech for tech-bros," Dr. Alex Morgan, partner at Khosla Ventures, said in a statement to Fortune. "This team has identified the larger underaddressed market of women interested in improving their health and wellness through getting insights specifically designed for women." The global femtech market is projected to nearly triple from $39 billion in 2024 to $97 billion by 2030. Clair Health's core argument is that the incumbents are retrofitting existing hardware. Its entire sensor architecture exists to model the HPO axis -- the hypothalamic-pituitary-ovarian system, the hormonal feedback loop that governs nearly every dimension of female physiology. The company holds provisional patents on that sensor configuration. "There's only so much of a moat you can build with hardware," Duan acknowledged. "What's really special is the machine learning approach and the biophysical modeling." Clair is launching as a wellness product in November and pursuing FDA clearance later -- the faster path to market. The company already has a 25,000-person waitlist and sold out its presale. It has received more than 100 letters of intent from fertility clinics. The longer-term roadmap includes perimenopause monitoring, hormone replacement therapy calibration, and diagnostics for conditions like PCOS and endometriosis. The company is building toward HIPAA compliance with zero-knowledge encryption and on-device computing for women who don't want health data stored in the cloud. Duan expects to raise more funding in roughly a year.