# Fast Slow vs Ayuna

The clearest difference is device support: Ayuna at 3 against Fast Slow's 1. Ayuna also leads on iOS requirement (15.1 vs 18.0). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Fast Slow sells 4 in-app purchases, starting at $1.99 per 7 days and Ayuna sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

Fast Slow ships an update every 2 weeks, Ayuna every 8 days. The most recent releases landed on October 24, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Fast Slow | Ayuna |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (39 ratings)](https://appshunter.io/ios/app/fast-slow-fasting-tracker/id6749188352/reviews)** | — |
| Number of ratings | **39** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Every 8 days** |
| Monetization | Free | — |
| Size | 23 MB | 43 MB |
| Requires iOS | 18.0 | **15.1** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Zan Cerne](https://appshunter.io/developer/1747198932) | [WEB3 SOLUTIONS LLC](https://appshunter.io/developer/1017521025) |

## What reviewers say

### Fast Slow

[App page](https://appshunter.io/ios/app/fast-slow-fasting-tracker/id6749188352)

Understand your body's metabolic changes during fasting with a visual timeline. This free app guides you through different fasting zones, from digestion to deep ketosis, and offers customizable schedules and smart notifications. It provides stats, streaks, and widgets for easy progress tracking.

**Highlights:** Fasting timer with visual timeline, 6 customizable fasting schedules, 5 distinct fasting zones explained, Smart notifications for fasting windows, Stats, streaks, and trends tracking, Home and Lock Screen widgets, Siri Shortcuts integration

**Features:** macOS Compatibility, Family Sharing, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Legacy | $1.99 | per 7 days |
| Legacy - Yearly | $12.99 | per year |
| Buy Me a Coffee | $2.99 | one-time |
| You're Amazing | $9.99 | one-time |


### Ayuna

[App page](https://appshunter.io/ios/app/ayuna-intermittent-fasting/id6766191902)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Monthly | $2.99 | per month |
| Premium Yearly | $19.99 | per year |


## Frequently asked questions

### Is Fast Slow free?

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

### Is Ayuna free?

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

### Do Fast Slow or Ayuna have ads?

Neither Fast Slow nor Ayuna shows ads.

### Which is updated more often, Fast Slow or Ayuna?

Fast Slow ships an update every 2 weeks, and Ayuna every 8 days. Most recently, Fast Slow was updated on October 24, 2026 and Ayuna on October 31, 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.*