Best Vitamin D Tracker
The only automatic vitamin D tracker that monitors your sun exposure and vitamin D synthesis in real-time. Clinical-grade accuracy, personalized intelligence, and effortless background operation.
Why Rays is the Best Vitamin D Tracker
For the best vitamin D tracker that automatically monitors your levels without any effort, Rays is the top choice. No other tracker offers this level of automation, accuracy, and personalization.
Automatic Tracking That Actually Works
Rays is the best vitamin D tracker because it's the only one that automatically detects when you're outdoors and tracks your vitamin D synthesis in real-time. No manual input required. Using GPS accuracy analysis, movement pattern recognition, step analysis, and light sensor data, Rays achieves 80-85% detection accuracy. The system learns your outdoor patterns at frequently visited locations and gets smarter over time, all while running efficiently in the background without draining your battery.
Real-Time Monitoring with Detailed Insights
Watch your vitamin D synthesis happen in real-time with detailed weekly charts, streak tracking, and comprehensive health insights. See exactly how much vitamin D you're producing, track your progress toward daily goals, and understand your patterns over time. Rays models scientifically-proven synthesis saturation (why production plateaus after 15-30 minutes) and automatically adjusts for seasonal variations, so you always have accurate, actionable data.
Clinical-Grade Accuracy You Can Rely On
Rays delivers professional-grade accuracy within ±15%, the same precision range found in clinical vitamin D studies. Our proprietary synthesis algorithm isolates UVB radiation (280-315nm), calculates precise solar elevation angles for your location, and combines this with your personal factors using research calibrated to Holick's Rule and Endocrine Society guidelines. You get the most accurate vitamin D tracking available, validated against peer-reviewed research.
Personalized Tracking for Your Unique Biology
Every calculation accounts for your Fitzpatrick skin type (I-VI), age-related synthesis decline, geographic location, seasonal UV variations, and lifestyle factors. A 70-year-old in Seattle gets different recommendations than a 25-year-old in Miami, because your body is unique. Rays personalizes every recommendation and safety limit for your specific profile, ensuring you get the most accurate vitamin D monitoring possible.
Background Operation That Respects Your Life
Rays works silently in the background, automatically detecting outdoor time without requiring any action from you. No manual logging, no timers to start, no sessions to remember. The system runs efficiently without impacting battery life, uses geohash clustering to protect your privacy, and gives you complete control through standard iOS/Android location permissions. Track your vitamin D without tracking your time.