UV Health

UV Health turns real-time UV data into a personal, easy-to-read reference for sun exposure — designed for people living at high latitudes, older adults, and anyone managing bone health. Key features: - Real-time UV Index for your location, with a plain-language risk label - A personal reference for sun-exposure time based on your Fitzpatrick skin type and how much skin is exposed - A redness (erythema) countdown so you know when to seek shade or reapply sunscreen - Sun timer and "My sun history": see each day's sessions and estimated vitamin D, stored only on your phone - A winter low-UV warning for high-latitude regions, where vitamin D synthesis may nearly stop for months - An optional module for AGA (male pattern) scalp exposure, based on the author's published Solar Window Hypothesis - Full-day UV forecast curve to help you plan outdoor time - Bilingual interface (English / Simplified Chinese), with a design built for larger text and easy tapping UV Health is built on the Solar Window Hypothesis, published by dermatologist Tingwei Zhang, MD, in Medical Hypotheses (2026): a bald AGA scalp faces the sun directly and without hair coverage, which may make it a more efficient site for vitamin D synthesis — relevant for people with reduced VDR efficiency who are working to maintain bone density. UV Health gives you reference information, not a medical diagnosis or treatment plan. All numbers are estimates based on modeled UV data, not a measurement on your skin. The app never suggests tanning or deliberately maximizing sun exposure — its purpose is sunburn prevention and a clearer, more personal picture of your vitamin D sun-time. Always talk to your doctor about your vitamin D levels, bone health, or any skin condition. UV Health is free to use. Sun-protection features (redness countdown, sunburn alert, disclaimers, and feedback) will always remain free. Have feedback? We read every message — use the in-app feedback link any time.