# CodonRX vs Fastology

The clearest difference is iOS requirement: CodonRX at 15.1 against Fastology's 17.0. On price, rating, ratings volume and update cadence there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 5.0 for CodonRX against 4.9 for Fastology. Both are backed by a comparable volume of ratings — 4 and 10 respectively.

Both ship on a similar rhythm, roughly every 3 weeks. The most recent releases landed on September 27, 2026 and September 26, 2026 respectively.

## The numbers

| Metric | CodonRX | Fastology |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (4 ratings)](https://appshunter.io/ios/app/codonrx/id6465990181/reviews)** | [4.9 (10 ratings)](https://appshunter.io/ios/app/fastology-fasting-tracker/id6761324779/reviews) |
| Number of ratings | 4 | **10** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 weeks | Every 3 weeks |
| Monetization | Free | Free |
| Size | 43 MB | 40 MB |
| Requires iOS | **15.1** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [Provaxus](https://appshunter.io/developer/1706820907) | [SmallScale Works LLC](https://appshunter.io/developer/1888909483) |

## What reviewers say

### CodonRX

[App page](https://appshunter.io/ios/app/codonrx/id6465990181)

This app helps users understand their digestive health by tracking symptoms, mood, and intake. It provides dosage reminders for a specific probiotic and visualizes progress over time. Designed as a companion to a scientifically advanced probiotic, it aims to empower users in managing their gut wellness.

**Highlights:** Symptom, mood, and intake logging, Probiotic dosage reminders, Progress visualization, Daily tracking, Insightful feedback on body response

**Features:** macOS Compatibility

**In-app purchases:** none


### Fastology

[App page](https://appshunter.io/ios/app/fastology-fasting-tracker/id6761324779)

This app provides structured tracking for intermittent fasting, going beyond simple timers. It helps users follow specific fasting schedules with clear phase progress, build consistency through streaks, and manage a flexible weekly plan. Focuses on discipline and reducing guesswork for a clearer fasting experience.

**Highlights:** Track various fast types (16:8, OMAD, extended), Live phase-by-phase progress tracking, Build streaks from completed fasts, Flexible weekly fasting schedule, Review fasting history, Ask fasting questions with reviewed answers, Siri and Shortcuts integration

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

**In-app purchases:** none


## Frequently asked questions

### Is CodonRX free?

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

### Is Fastology free?

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

### Which has better reviews, CodonRX or Fastology?

CodonRX is rated higher. CodonRX averages 5.0 out of 5 from 4 ratings, while Fastology averages 4.9 from 10 ratings.

### Do CodonRX or Fastology have ads?

Neither CodonRX nor Fastology shows ads.

### Which is updated more often, CodonRX or Fastology?

CodonRX ships an update every 3 weeks, and Fastology every 3 weeks. Most recently, CodonRX was updated on September 27, 2026 and Fastology on September 26, 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.*