Comparison

72Hour Fasting Timer vs Fast36

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

72Hour Fasting Timer

This app assists users in tracking extended fasting periods of 24, 48, or 72 hours. It provides progress zones, statistics, and reminders to help users stay focused and motivated during their fasting journey.

Highlights
  • Smart fasting timer
  • Progress zones (fat burning, autophagy)
  • Statistics and history
  • HealthKit sync
  • Notifications and reminders
  • Minimalist design
Features
Read full description

Fasting Timer 72 is your personal companion for extended fasts (24h, 48h, 72h). Whether you're doing intermittent fasting, OMAD, or long-term fasting, this app helps you track progress, stay focused, and stay motivated. Features: - Smart fasting timer - Progress zones (fat burning, autophagy, etc.) - Statistics and history - HealthKit sync (optional) - Notifications and reminders - Minimalist design. No ads. Just fasting — tracked right.

About

Fast36

Features
Read full description

Stages, not streaks. Fast36 is the fasting app for people who care about the metabolic arc, not the calendar grid. Track the biochemical progression of a 24 to 72+ hour fast with phase-aware timing, in-the-moment science, and a private record of every session. WHAT YOU GET • Stage-aware timer. Watch your fast move through the four metabolic regimes — glycogen depletion, ketosis, autophagy, deep autophagy — with color-coded thresholds that match real human physiology. • Quick Log for ketones and glucose. Pair every fast with a finger-stick reading. Build a longitudinal record of how your biomarkers respond to each protocol. • Live Activity on the Lock Screen. Current stage, elapsed time, and next threshold — always one glance away. No need to open the app. • Apple Watch companion. Start, monitor, and end fasts from your wrist. Phone, iPad, and watch always show the same session. • History with substance. Total hours, per-stage distribution, per-fast gantt, readings, notes. No streaks. No flame emoji. No celebratory confetti. • The Science reference. Peer-reviewed citations for every stage claim. We tell you what's proven in humans and what's extrapolated from rodent studies, and when evidence is emerging rather than settled. FREE • 36-hour protocol — the namesake fast • Stage-aware timer and Stages reference • History log and HealthKit integration • On-device privacy FAST36 PRO — $14.99 / month or $99 / year • 24-hour reset fasts • 48-hour and 72-hour extended protocols • Custom fast lengths • Live Activity with stage transitions • Stage-crossing haptics • Apple Watch companion • Quick Log for ketones and glucose • Full history analytics and stage distribution chart • Notes on every fast • Apple Health bidirectional sync • The Science deep-dive with citations WHO IT'S FOR Biohackers running 24 / 36 / 48 / 72-hour protocols. People who want their fasting app to read like a lab notebook, not a game. Anyone who has ever said "autophagy" at dinner and meant it. Not for calorie counting, not for weight-loss streaks, not for "gamified wellness." PRIVACY All fasting data lives on-device. Optional Apple Health sync stays between you and Apple — it does not pass through our servers. No accounts, no newsletters, no behavioral tracking, no third-party analytics. Not medical advice. Extended fasting carries real risks for people with diabetes, eating disorder history, pregnancy, low body fat, or on medications affecting blood sugar or blood pressure. Consult a clinician before attempting any fast over 24 hours. Fast36 Pro subscriptions renew automatically unless cancelled at least 24 hours before the current period ends. Manage or cancel from your Apple ID settings. Terms of Use: https://fast36.app/terms Privacy Policy: https://fast36.app/privacy Support: hello@fast36.app

Screenshots

72Hour Fasting Timer4 screens
Fast364 screens

Verdict

The call

The clearest difference is price: Fast36 at Free against 72Hour Fasting Timer's $1.99. 72Hour Fasting Timer's advantage is in-app purchases (none vs 2) and chart position (#83 vs unranked). On ads and device support 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

CostPrice · In-app purchases · Ads · Monetization

Fast36 is free to download; 72Hour Fasting Timer costs $1.99 up front. Fast36 sells 2 in-app purchases, starting at $14.99 per month. 72Hour Fasting Timer asks for nothing beyond the download.

Scorecard4 real differences · 7 level
72Hour Fasting Timer versus Fast36: the parameters behind the verdict, then further details
Parameter72Hour Fasting TimerFast36
Price$1.99Free — better
Rating4.3 (3 ratings) — better—
Positive reviews66.7% of reviews—
Number of ratings3 — better—
Update frequencyEvery 7 months—
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaid—
Best chart rank#83 — better—
DevicesiPhone, iPad, iPodiPhone, iPad, Apple Watch
Requires iOS14.0 — better17.0
Further details — not scored
Size5 MB7 MB
Age rating17+4+
DeveloperPOWER SATELLITE LLCAKN Technologies FZ-LLC

In-app purchases

None

72Hour Fasting Timer

No in-app purchases

2 purchases

Fast36

Subscriptions2
  • Fast36 Pro - Monthly$14.991 Month
  • Fast36 Pro - Yearly$99.991 Year

Questions

Is 72Hour Fasting Timer free?
72Hour Fasting Timer costs $1.99, with no in-app purchases.
Is Fast36 free?
Fast36 is free to download, with in-app purchases available.
Do 72Hour Fasting Timer or Fast36 have ads?
Neither 72Hour Fasting Timer nor Fast36 shows ads.

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