Flo has 380 million downloads and a Perimenopause Score. Kairos™ has four computation engines, 8 clinical domains, STRAW+10 staging, and a fellowship-trained surgeon behind the design.
Kairos™ was built by Dr. Shannon Carpenter — a fellowship-trained orthopedic surgeon who runs The Bone Health Clinic — as the patient-facing layer of her deployed clinical system. Four computation engines score symptoms across eight clinical domains, classify reproductive aging through STRAW+10, and flag clinically significant transitions automatically. It tracks both women and men, monitors bone health as a first-class domain, and generates provider-ready reports designed for a 15-minute appointment. Through provider integration, Kairos™ prescribes — backed by continuous clinical intelligence, not a one-time questionnaire. It supports insurance-backed and cash-pay care on the same platform. No other app in this space is built on a live clinical backend, and none of them can replace what takes four or five apps to approximate.
380 million downloads. Flo has the largest women's health user community on the planet, with anonymous peer support via Secret Chats and a library of health articles. That community is a genuine asset.
Flo tracks periods, fertility windows, and pregnancy — and now perimenopause. If you want a single app across your entire reproductive life, Flo covers more lifecycle stages than Kairos™.
Flo launched perimenopause-specific features in 2025, including a single composite Perimenopause Score and a projected Menopause Timeline. It's a starting point for awareness.
Flo's AI assistant answers health questions and surfaces personalized tips. For general wellness guidance, it's accessible and easy to use.
Flo's Perimenopause Score is a single composite number. Kairos™ runs four distinct engines: a Symptom Burden engine scoring 8 clinical domains independently (0–100 each), a Cycle Variability engine with statistical analysis of cycle length changes, STRAW+10 reproductive staging with confidence levels and explanation bullets citing your specific data, and clinically significant Event Detection that flags vasomotor onset, sleep decline, and cycle jumps as they happen — not in retrospect.
Kairos™ was founded by Dr. Shannon Carpenter, a fellowship-trained orthopedic surgeon who runs The Bone Health Clinic. The computation engines reflect how a clinician actually evaluates a patient — not how a tech company decided to add menopause features to capture a growing market. That difference shows in the data.
Kairos™ is not a standalone app. It is the patient-facing layer of TBHC PTA, a deployed clinical system running in a real practice. The scoring engines were built to support real treatment decisions — not to generate engagement metrics.
Kairos™ classifies your reproductive stage using the STRAW+10 framework — the clinical gold standard for staging reproductive aging — and shows you the confidence level alongside the specific data points that determined the classification. Flo's Menopause Timeline is a projection. Kairos's staging tells you where you actually are and shows its work.
Kairos™ scores symptom burden across 8 clinical domains: vasomotor, sleep, mood, cognitive, musculoskeletal, sexual health, urogenital, and metabolic. Each domain gets an independent 0–100 score. Flo logs symptoms but does not score them clinically or decompose them into distinct domains.
Kairos™ detects and surfaces clinically meaningful transitions — vasomotor symptom onset, significant sleep decline, sudden cycle length jumps — as they occur in your data. Flo does not offer event detection; it surfaces historical summaries.
Kairos™ accepts both insurance and cash pay, and generates provider-shareable reports designed for clinical conversations. Flo has no provider integration, no clinical report generation, and no insurance pathway.
Kairos™ includes bone health monitoring — a critical dimension of midlife health that Flo does not address at all — and supports men's health tracking for testosterone decline and andropause. Flo is exclusively a women's reproductive tracker.
Flo is the most downloaded women's health app ever built, and its 2025 perimenopause features show that the market is paying attention. The community, the lifecycle coverage, and the AI assistant are real advantages — Flo has scale that Kairos™ does not. But Flo's Perimenopause Score is one number. Kairos runs four computation engines producing 8 independently scored clinical domains, statistically analyzed cycle variability, STRAW+10 reproductive staging with explained confidence, and clinically significant event detection. Flo was built by a tech company that added midlife features. Kairos was built by Dr. Shannon Carpenter, a fellowship-trained orthopedic surgeon who treats these patients — as the patient-facing layer of a deployed clinical system. If you want the world's most popular period tracker with a perimenopause mode, Flo is the answer. If you want clinical-grade intelligence, provider integration, insurance support, and a system built for midlife from the ground up, Kairos is in a different category.
Kairos™ tracks, scores, and interprets the symptoms of midlife hormonal change — for both women and men.