# Protocol66 — Build yourself in 66 days

> Build yourself in 66 days (iPhone/iPad app by Pocket Apps Studio Pte. Ltd..)

- Source: https://appshunter.io/ios/app/protocol66/id6757076988 (this page in markdown: same URL + `.md`)
- Developer: [Pocket Apps Studio Pte. Ltd.](https://appshunter.io/developer/1864339139)
- Category: Productivity, Health & Fitness
- Price: Free with in-app purchases
- Age rating: 12+
- Requires: iOS 18.0 · 35 MB
- Released: 2026-01-12
- Data updated: 2026-01-31
- User reviews in markdown: https://appshunter.io/ios/app/protocol66/id6757076988/reviews.md

## What is Protocol66?

66 days. 5 habits. Miss a day, start over.

Protocol 66 is the science-backed alternative to extreme fitness challenges. Based on habit formation research — not bro science — it takes exactly 66 days to build lasting habits.

THE RULES ARE SIMPLE
- Pick 5 daily habits
- Complete all 5 every day
- Miss a day, restart from zero
- Rest days are earned, not given

WHY 66 DAYS?
Research by Phillippa Lally at University College London found it takes an average of 66 days to form automatic habits. Not 21. Not 30. Not 75.

THIS ISN'T FOR EVERYONE
No streaks to protect you. No lives. No second chances. If you're looking for an app that goes easy on you, this isn't it.

Ready to commit?

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Privacy Policy: https://www.pocketapps.studio/protocol66/privacy
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Pro | $19.99 | per year |
| Pro Version | $2.99 | per 7 days |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Lifetime Access | $3.99 | one-time |



## Version history (last 2 releases)

### 1.0.1 — 2026-01-29

Version 1.0.1
  • Late Logging - Forgot to log yesterday? Now you can catch up before your challenge fails
  • Challenge Failed Card - Clear visibility when challenges end with easy restart options
  • FAQ Section - Find answers to common questions in Profile
  • Better Notifications - Stay on track with evening reminders and milestone celebrations
  • Bug fixes and performance improvements for iOS 26

### 1.0.0 — 2026-01-12

No release notes.

## More apps by Pocket Apps Studio Pte. Ltd.

- [Learn Chinese - XueTang](https://appshunter.io/ios/app/learn-chinese/id6743937874)

All apps by Pocket Apps Studio Pte. Ltd.: https://appshunter.io/developer/1864339139

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-01-31.*