Comparison

Fast36 vs FastLyfe

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

Head to head
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 β€’ Stage-aware timer. Watch your fast move through the four metabolic regimes β€” glycogen depletion, ketosis, autophagy, deep autophagy β€” with color-coded thresholds that match real human physiology. β€’ 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. β€’ Live Activity on the Lock Screen. Current stage, elapsed time, and next threshold β€” always one glance away. No need to open the app. β€’ Apple Watch companion. Start, monitor, and end fasts from your wrist. Phone, iPad, and watch always show the same session. β€’ History with substance. Total hours, per-stage distribution, per-fast gantt, readings, notes. No streaks. No flame emoji. No celebratory confetti. β€’ 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 β€’ 36-hour protocol β€” the namesake fast β€’ Stage-aware timer and Stages reference β€’ History log and HealthKit integration β€’ On-device privacy FAST36 PRO β€” $14.99 / month or $99 / year β€’ 24-hour reset fasts β€’ 48-hour and 72-hour extended protocols β€’ Custom fast lengths β€’ Live Activity with stage transitions β€’ Stage-crossing haptics β€’ Apple Watch companion β€’ Quick Log for ketones and glucose β€’ Full history analytics and stage distribution chart β€’ Notes on every fast β€’ Apple Health bidirectional sync β€’ 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 β€” 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

About

FastLyfe

Features
Read full description

FastLyfe: Fasting Tracker & Timer FastLyfe is an easy-to-use fasting tracker designed to help you stay consistent and build better habits. Track your fasts, follow popular fasting schedules, and monitor your progress over timeβ€”all in one simple app. Features: Fasting timer to track your sessions Popular protocols like 16:8, 18:6, and OMAD Custom fasting schedules Progress tracking and history Calendar view to see your consistency Clean and simple design FastLyfe is built for anyone looking to stay on track with intermittent fasting without distractions or unnecessary complexity.

Screenshots

Fast364 screens
FastLyfe4 screens

Verdict

The call

The clearest difference is iOS requirement: FastLyfe at 13.0 against Fast36's 17.0. On price, ads, in-app purchases and device support there is nothing between them.

Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS

CostPrice Β· In-app purchases Β· Ads Β· Monetization

Both are free to download. Fast36 sells 2 in-app purchases, starting at $14.99 per month and FastLyfe sells 3 in-app purchases, starting at $5.99 per month. Whichever you choose, the download price is not the number that matters.

Scorecard1 real difference Β· 5 level
Fast36 versus FastLyfe: the parameters behind the verdict, then further details
ParameterFast36FastLyfe
PriceFreeFree
Update frequencyβ€”Every 6 weeks
AdsNoNo
In-app purchasesYesYes
DevicesiPhone, iPad, Apple WatchiPhone, iPad, iPod
Requires iOS17.013.0 β€” better
Further details β€” not scored
Size7 MB31 MB
Age rating4+4+
DeveloperAKN Technologies FZ-LLCCayden Williams

In-app purchases

2 purchases

Fast36

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

FastLyfe

Subscriptions2
  • Monthly3 Days trial$5.991 Month
  • Yearly$16.991 Year
One-time1
  • Lifetime Pro$29.99

Questions

Is Fast36 free?
Fast36 is free to download, with in-app purchases available.
Is FastLyfe free?
FastLyfe is free to download, with in-app purchases available.
Do Fast36 or FastLyfe have ads?
Neither Fast36 nor FastLyfe shows ads.

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