# FastZen vs Mu.

The clearest difference is in-app purchases: Mu. at none against FastZen's 5. Mu. also leads on device support (3 vs 1) and iOS requirement (18.6 vs 26.0). On price, update cadence and ads there is nothing between them.

Both are free to download. FastZen sells 5 in-app purchases, starting at $1.99 per 7 days. Mu. asks for nothing beyond the download.

FastZen ships an update every 5 days, Mu. every 10 days. The most recent releases landed on October 9, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | FastZen | Mu. |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (9 ratings)](https://appshunter.io/ios/app/fastzen-intermittent-fasting/id6744087602/reviews)** | — |
| Number of ratings | **9** | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 5 days** | Every 10 days |
| Monetization | Freemium | — |
| Size | 27 MB | 34 MB |
| Requires iOS | 26.0 | **18.6** |
| Devices | iPhone | **iPhone, iPad, Apple Watch** |
| Age rating | 4+ | 12+ |
| Developer | [MefjuDev LLC](https://appshunter.io/developer/1777787735) | [Liminal Pictures](https://appshunter.io/developer/1895974335) |

## What reviewers say

### FastZen

[App page](https://appshunter.io/ios/app/fastzen-intermittent-fasting/id6744087602)

This app helps you manage your intermittent fasting journey with custom schedules, progress tracking, and smart reminders. Achieve your weight loss and energy goals with a clean, intuitive interface and motivational features.

**Highlights:** Custom fasting schedules (16:8, 20:4, OMAD, up to 168 hours), Progress tracking with history, streaks, and insights, Smart reminders for fasting start and end times, Achievements and milestones for motivation, Calendar view of completed fasts, Light and dark mode, Widgets

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly | $1.99 | per 7 days |
| Monthly | $2.99 | per month |
| 3 Months | $7.99 | per 3 months |
| Yearly | $19.99 | per year |
| Lifetime | $39.99 | one-time |


### Mu.

[App page](https://appshunter.io/ios/app/mu/id6766069551)

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is FastZen free?

FastZen is free to download, with in-app purchases available.

### Is Mu. free?

Mu. is free to download, with no in-app purchases.

### Do FastZen or Mu. have ads?

Neither FastZen nor Mu. shows ads.

### Which is updated more often, FastZen or Mu.?

FastZen ships an update every 5 days, and Mu. every 10 days. Most recently, FastZen was updated on October 9, 2026 and Mu. on October 28, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*