CHALLENGE
Summer Sun Challenge
Hit your daily vitamin D goal each day. Watch your streak grow and fill your summer calendar in Stats.
Rays: Auto Vitamin D Tracking
Auto sun exposure tracking
Only for iPhone
Free · In‑App Purchases
iPhone
3-day free trial! Automatically track vitamin D from sun exposure and supplements, get personalized recommendations, and optimize your health
Never Worry About Vitamin D Again
Over 1 billion people are vitamin D deficient, but knowing if you’re getting enough sun shouldn’t be complicated. Rays is the world’s first app that automatically tracks your vitamin D synthesis, so you can spend your time enjoying life. No manual logging, no thinking required.
Why Vitamin D Matters Optimal vitamin D levels support natural energy, balanced mood, healthy sleep cycles, and radiant skin. With Rays’ precise tracking, you can maintain these benefits year-round without guesswork or overdoing it.
Automatic Vitamin D Tracking Rays uses a first-of-its-kind outdoor detection system combining GPS precision patterns, sensor data, movement analysis, and personalized machine learning that adapts to your routines. With high accuracy and minimal battery usage, it works seamlessly in the background without any manual input.
Personalized Health Intelligence Our algorithm analyzes your skin type (Fitzpatrick Scale I-VI), age, geographic location, supplement intake, and lifestyle factors. Based on Endocrine Society Clinical Practice Guidelines, we provide recommendations as precise as your doctor’s, but as convenient as checking the weather.
Smart Recommendations Receive personalized guidance like “Get 18 minutes at 11 AM tomorrow” based on real-time UV index, cloud cover, solar positioning, and your personal synthesis rate. Our intelligent engine suggests optimal timing when UV will be 2-3x more efficient for vitamin D production.
Advanced Progress Tracking Monitor your vitamin D synthesis with detailed weekly charts, streak tracking, and comprehensive health insights. Seamlessly syncs with Apple Health and automatically adjusts for seasonal variations while preventing excessive intake when combined with supplements.
For Tanners & Sun Enthusiasts Already spending time in the sun for a tan? Put that exposure to work. Rays tracks your cumulative UV dose so you can optimize your color, avoid overexposure, and know exactly where you stand — all automatically.
Rays is perfect for health-conscious individuals who want optimal vitamin D without the guesswork.
Try Rays free for 3 days with full access to all features.
Terms of Use: https://getrays.app/eula
Privacy Policy: https://getrays.app/privacy
Health Disclaimer: https://getrays.app/health-disclaimer
Events
- Bug fixes
The developer, Rays Health Technologies LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Health & Fitness
- Location
- Contact Info
- Identifiers
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Rays Health Technologies LLC
- Size
- 59.4 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 15.1 or later.
- iPhone
Requires iOS 15.1 or later. - iPod touch
Requires iOS 15.1 or later.
- iPhone
- Location
- This app may use your location even when it isn’t open, which can decrease device battery life.
- Languages
- English
- Age Rating
9+
- 9+
- Contains
Health or Wellness Topics
- In-App Purchases
Yes
- Rays - Auto Vitamin D Tracker $19.99
- Rays - Auto Vitamin D Tracker $4.99
- Copyright
- © 2026 Rays Health Technologies LLC