SunGuard vs SolGlow
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
SunGuard
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The app dynamically adapts to your behavior: If you move into the shade or partial shade, your remaining sun exposure time is recalculated with a single tap. The same applies to activities like swimming, sweating, or spending time on reflective surfaces such as snow or sand. This ensures your estimate remains realistic and up-to-date at all times. You’ll be notified in time before your skin is damaged. The app also reminds you when to reapply sunscreen—for optimal protection all day long. Transparency is key: In the Info section, all calculations are clearly explained, and you’ll find in-depth information about UV radiation, skin types, and effective sun protection. The free version already offers all the essential features to reliably protect you from the sun. With the Pro version, you get even more out of the app: • Create multiple profiles and conveniently manage your whole family • Start tracking your sun exposure retroactively if you forgot to open the app in the morning • One-time purchase for €9.99 – ad-free for life Whether in everyday life, on vacation, or while exercising—this app adapts to you and helps you enjoy your time in the sun safely and mindfully. Not medical advice or a medical device!
SolGlow
This app automatically estimates your daily vitamin D intake based on sunlight exposure, skin type, and location. It provides real-time UV index, burn-safe time remaining, and integrates with Apple Watch for effortless tracking. Features include winter mode, supplement check-ins, and advanced planning tools for Pro users.
- Automatic vitamin D estimation
- Live UV index and IU-per-minute rate
- Burn-safe time remaining with alerts
- Winter Mode for low-sun periods
- Supplement check-in
- 7-day UV forecast (Pro)
- Trip Planner for jet lag (Pro)
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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/
Screenshots
Verdict
The clearest difference is iOS requirement: SunGuard at 15.1 against SolGlow's 17.2. On price, update cadence, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. SunGuard sells 1 one-off in-app purchase and SolGlow sells 2 in-app purchases, starting at $9.99 per year. Whichever you choose, the download price is not the number that matters.
SunGuard ships an update weekly, SolGlow every 10 days. The most recent releases landed on October 4, 2026 and October 24, 2026 respectively.
| Parameter | SunGuard | SolGlow |
|---|---|---|
| Price | Free | Free |
| Rating | — | 3.7 (3 ratings) — better |
| Positive reviews | — | 50.0% of reviews |
| Number of ratings | — | 3 — better |
| Update frequency | Weekly — better | Every 10 days |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | — | Freemium |
| Devices | iPhone, iPod | iPhone, iPad, Apple Watch — better |
| Requires iOS | 15.1 — better | 17.2 |
| Further details — not scored | ||
| Size | 52 MB | 10 MB |
| Age rating | 4+ | 12+ |
| Developer | Patrick Schmutz | Michael Smith |
In-app purchases
SunGuard
- SunGuard Pro$8.99
SolGlow
- SolGlow Pro Annual$9.991 Year
- SolGlow Pro$19.99









