Track Your Vitamin D
From the Sun
Know when to go outside, how much D you're making, and stay safe from burns. 14 years of science-backed tracking.
Know when to go outside, how much D you're making, and stay safe from burns. 14 years of science-backed tracking.
42% of Americans are Vitamin D deficient
Studies link deficiency to diabetes, heart disease, depression, and increased cancer risk.
dminder calculates exactly when UVB is available at your location. Plan sessions by choosing a vitamin D target or a time limit — the app handles the rest.
Uses real-time solar position, atmospheric ozone from NOAA satellites, and your skin type to estimate production rates.
Track your session in real time. The timer shows vitamin D earned, elapsed time, and warns you before you burn. Works on your lock screen and Apple Watch too.
Minute-by-minute erythemal dose integration means accuracy even as the sun moves across the sky.
dminder continuously estimates your blood vitamin D level based on sun sessions, supplements, and food. Analog gauges show your daily progress and current status at a glance.
Enter lab results to calibrate. The projection engine forecasts where your level is headed over the next 90 days.
Log sun sessions, supplements, food sources, and imported outdoor workouts in one place. See your full vitamin D history and understand exactly where your intake comes from.
No sun? No problem. D-Minder tracks vitamin D from UV lamps too. Configure your lamp's UV output once, then track sessions just like outdoor sun exposure.
Currently supports Sperti Fiji Sun and Mitolux Red Light lamps, with more coming.
Sperti Fiji Sun
Mitolux
NOAA JPSS Satellite — Source: NESDIS
Atmospheric ozone is the biggest variable in UV intensity — and most apps ignore it. D-Minder downloads a live 360x180 ozone grid from NOAA's OMPS satellite instruments, updated multiple times daily.
The difference between 250 and 350 Dobson Units of ozone can change your vitamin D production by 40%. We don't guess — we measure.
Native apps on both platforms with Apple Watch and Wear OS support.
Every screen designed for both light and dark modes.
D-Minder's vitamin D engine is built on peer-reviewed science and protected by U.S. Patent 9,008,389.
The entire calculation engine is written in Rust and shared across iOS and Android — identical science on every platform.
"Thanks for such a cool App!!! I can't believe there is something available to help us with such an important factor for our health!! Thanks so much for such a great idea!!"
— Jennifer
"Very cool app. Thanks for doing this."
— Bruce
"Really love your app, well done."
— Brendan
"I absolutely LOVE your app. Thanks so much."
— Tara
Start sessions, check UV conditions, and track vitamin D right from your wrist. Full companion apps for both Apple Watch and Wear OS.
Apple Watch
Complications, Live Activity, session control
Wear OS
Tiles, session tracking, UV display
University lecture by Dr. Michael F. Holick, the leading researcher on vitamin D and sun exposure.
A quick explainer on how your body produces vitamin D from sunlight and why it matters.
Features we're building next to make D-Minder even more powerful.
Join anonymized research studies to help advance vitamin D science. Contribute your data to real research while keeping your privacy intact.
When you approach your predicted burn time, the app prompts you to check your skin. For lighter skin types, the camera detects redness before you can see it. For darker skin (Type V/VI), a sensation-based check asks about warmth and tenderness — because melanin masks visible redness but can't mask how your skin feels. Future versions will use CIELAB color space analysis to detect inflammation even in the darkest skin tones.
A full Android watch companion app. Start sessions, check UV conditions, and track vitamin D right from your wrist.
See where your vitamin D level is heading based on your habits. A 90-day forecast that shows whether you're on track or falling behind.
Sufficiency streaks, milestones, and achievements. Stay motivated with rewards for consistent vitamin D habits.
Free on iOS and Android.
