SolGlow: Vitamin D Tracker
Michael Smith Health & Fitness iPhoneiPadiPod touchApple Watch
SolGlow: Vitamin D Tracker is a free Health & Fitness app for iPhone and iPad by Michael Smith. Rated 3.7/5 from 3 ratings. Requires iOS 17.2.
- Rating
- 3.7
- 3 ratings
- Price
- Free
- on the App Store
- Size
- 10 MB
- Age 12+
- Updated
- Oct 23
- 2026 · v2.0
Screenshots
About SolGlow: Vitamin D Tracker
SolGlow turns your time outside into the number that matters: vitamin D — measured in IU, not just minutes. And it's automatic: your Apple Watch's daylight is credited to your estimate by itself — no logging, no GPS trail — and every number can show the exact math behind it. From your Time in Daylight, skin type, outfit, age, and your location's sun angle, SolGlow estimates the vitamin D you actually made today — and warns you before you burn. SUN TODAY, IN ONE ANSWER (NEW) • When today's vitamin D window opens — the same UV 3+ hours that call for sun protection • Your burn time, and the protection today's UV calls for: SPF, sunglasses, shade • Optional alerts when today's protection hours begin • Live UV index, one daily goal tuned to your life stage, and vitamin-D foods in your units SUN SAFETY THAT KNOWS YOU (NEW, FREE) • Sun Sensitivity: taking a medicine that can increase sun sensitivity? Every burn time gets a cautious margin • Snow, sand or water bounce extra UV at you — tell SolGlow and today's burn math adjusts • Monthly Skin Check: the ABCDE self-exam with a gentle reminder — a habit, never a diagnosis AUTOMATIC, AND YOU CAN SEE WHY (FREE) • True-D: SolGlow corrects the UV Index for ozone — sunburn UV isn't vitamin-D UV — and shows the cited step whenever it changes your number (Kazantzidis 2009) • Learn & Sources: plain-language guides to UV, sunscreen, winter and more, each with its studies • Ask Siri "How much sun did I get in SolGlow?" — plus Best Sun Window widgets for StandBy, Lock Screen, and Home Screen MADE FOR IPHONE DUO Open it and Today spreads into two columns, guides read like a book, and a live session stands up like a scoreboard on the picnic table. OWN THE WINTER • Winter Mode: when your latitude's noon sun can't make vitamin D, SolGlow shows where yours is coming from — and counts down to the sun's return • Free Winter Countdown widget and Apple Watch complication — works offline • Streak Shield: only physics can excuse a missed day • One-tap supplement check-in from a notification, widget, Siri, or your watch BRING YOUR HISTORY (FREE) • Import your Time in Daylight history from Apple Health in one tap — no account • Back up everything to one file and restore on a new phone SUN SESSIONS (PRO) • Direct Sun: a live burn budget that only counts down, and says plainly when to get out • Live Activity on your Lock Screen and Dynamic Island, with a sunscreen reapply timer • Morning Light, editable history, streaks, a shareable weekly recap — and the Apple Watch app PLAN AHEAD (PRO) • 7-day UV forecast with your personal best-sun windows • Annual sun plan and a jet-lag Trip Planner (timing guidance, not medical advice) KNOW YOUR LEVEL (PRO) • 25(OH)D serum estimate with a 12-week projection • Cofactors, supplement guidance, blood-test reminders, and a doctor-ready PDF/CSV report PRIVATE BY DESIGN No account. No sign-up. No analytics. No ads. Your health data, profile, and location history never leave your device — the only network call fetches a UV forecast (coordinates only, no identifier). Optional backup goes to your own iCloud, never to us. FREE TO TRY — THEN PICK YOUR PLAN Every feature free for 14 days. Then choose your SolGlow Pro: $9.99 per year, auto-renewing until you cancel — or Lifetime: one purchase, yours forever, Family Sharing included. The free tier keeps today's tracking and all safety features, always. SolGlow estimates are educational, not medical advice. Always consult your clinician about vitamin D supplementation and blood testing. SolGlow Pro Annual is an auto-renewing subscription: $9.99 per year, charged to your Apple ID at purchase confirmation. It renews unless cancelled at least 24 hours before the period ends. Manage or cancel in your App Store settings. SolGlow Pro Lifetime is a one-time purchase that never renews. Privacy Policy: https://twisteddatastudios.com/privacy.html Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
What’s new
Version 2.0 · Updated October 23, 2026
SolGlow 2.0: one clear answer about your sun, every day. SUN TODAY (NEW) Today now opens on one answer: when your vitamin D window opens — the same UV 3+ hours that call for sun protection — how long until you'd burn, and the protection today's UV calls for. Turn on protection alerts and SolGlow gives you a heads-up when those hours begin. SUN SENSITIVITY (NEW, FREE) Some common medicines make skin burn faster. Tell SolGlow you take one and every burn time gets a cautious margin. Heading to the beach, the lake or the slopes? Pick today's surroundings — sand, water or snow — and the burn math accounts for the extra UV they reflect. MONTHLY SKIN CHECK (NEW, FREE) A guided ABCDE self-exam with a monthly reminder. It helps you learn what's normal for your skin — it never analyzes photos or diagnoses anything. LEARN & SOURCES (NEW, FREE) Plain-language guides to the UV Index, sunscreen, vitamin D in winter, medications and more — each one with the studies behind it, plus how SolGlow calculates every number. MADE FOR IPHONE DUO Open it and Today spreads into two columns, Learn reads like a book, and the Solstice Story pages in spreads. Fold it like a laptop during a sun session and the clock sits up top, readable from your towel, with the controls on the flat half. Stand it like a tent for a one-row scoreboard. ALSO NEW • A start-session button right on the Sun Today card • Smoother share cards and Solstice Stories, and a fix for a story sheet that could open blank • Dozens of reliability fixes across the app, widgets and Apple Watch As always: no accounts, no analytics, no ads. Estimates are educational, not a diagnosis — always consult your clinician about vitamin D and blood testing.
App privacy
The developer, Michael Smith, reported these privacy practices to Apple.
Data Not Linked to You
The following data, which may be collected but is not linked to your identity, may be used for the following purposes:
- Location: Precise Location
Used for: App Functionality
Alternatives to SolGlow: Vitamin D Tracker
Looking for apps like SolGlow: Vitamin D Tracker? Here are 6 similar apps on the App Store. The highest rated is Vitamin D Window Widget (5.0/5), and all 6 are free to download.
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Vitamin D Window Widget
5.0
-
Sunshine Pal :VitaminD Tracker
5.0
-
RayDay: Vitamin D Tracker
3.0
-
Rays: Auto Vitamin D Tracking
4.4
-
Vitamin D Sun Tracker - Bask
4.8
-
UV Index, Vitamin D & Sunburn
5.0
| App | Rating | Price | Last updated | Compare |
|---|---|---|---|---|
| SolGlow: Vitamin D Tracker | 3.7 / 5 (3 ratings) | Free | October 23, 2026 | |
| Vitamin D Window Widget | 5.0 / 5 (2) | Free | Aug 12, 2026 | Compare |
| Sunshine Pal :VitaminD Tracker | 5.0 / 5 (7) | Free | Oct 15, 2026 | Compare |
| RayDay: Vitamin D Tracker | 3.0 / 5 (2) | Free | Oct 29, 2026 | Compare |
| Rays: Auto Vitamin D Tracking | 4.4 / 5 (7) | Free | Nov 1, 2026 | Compare |
| Vitamin D Sun Tracker - Bask | 4.8 / 5 (29) | Free | Jul 9, 2026 | Compare |
| UV Index, Vitamin D & Sunburn | 5.0 / 5 (1) | Free | Jul 28, 2026 | Compare |