# Katalyst vs Fiix Body

The clearest difference is monetization model: Fiix Body at free against Katalyst's free with in-app purchases. Fiix Body also leads on ratings volume (298 vs 59). Katalyst's advantage is review sentiment (81% vs 67%). On price, rating, update cadence and ads there is nothing between them.

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

Fiix Body holds the better App Store score, 4.7 against 4.6. That said, the two scores are not equally well evidenced: Fiix Body has 298 ratings behind it against 59, so its average is the more settled of the two. Written reviews complicate that: 81% of Katalyst's written reviews are positive against 67% of Fiix Body's, so the app with the better star average is not the one people write more warmly about.

Katalyst ships an update every 3 weeks, Fiix Body every 5 weeks. The most recent releases landed on October 25, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Katalyst | Fiix Body |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.6 (59 ratings)](https://appshunter.io/ios/app/katalyst/id1558163458/reviews) | **[4.7 (298 ratings)](https://appshunter.io/ios/app/fiix-body/id1562886855/reviews)** |
| Number of ratings | 59 | **298** |
| Positive reviews | **80.6% of reviews** | 66.7% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 5 weeks |
| Monetization | Free with in-app purchases | **Free** |
| Size | 155 MB | 33 MB |
| Requires iOS | 16.0 | **15.6** |
| Devices | iPhone, iPad, Apple Watch | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Katalyst Interactive Inc.](https://appshunter.io/developer/1558163460) | [Fiix Body](https://appshunter.io/developer/1850967876) |

## What reviewers say

### Katalyst

[App page](https://appshunter.io/ios/app/katalyst/id1558163458)

This app enhances a revolutionary workout system using Electro Muscle Stimulation (EMS) to engage all muscles simultaneously. It offers a full-body workout in just 20 minutes, with zero joint load. Access diverse workout programs and control intensity for personalized training.

**Highlights:** Electro Muscle Stimulation (EMS) training, Full-body engagement, 20-minute workouts, Zero joint load, Diverse workout library (strength, power, cardio, recovery), Adjustable impulse intensity, Offline workout access

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

**In-app purchases:** none


### Fiix Body

[App page](https://appshunter.io/ios/app/fiix-body/id1562886855)

This digital physical therapist guides you through elbow pain recovery at home. It provides personalized therapy schedules, tracks your progress with data and surveys, and offers helpful tips and videos to maximize your treatment experience.

**Highlights:** Personalized therapy schedules, Progress tracking and weekly scores, Pain assessment surveys, Comparison graphs with other users, Helpful tips and video guides, Push notification reminders

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Katalyst free?

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

### Is Fiix Body free?

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

### Which has better reviews, Katalyst or Fiix Body?

Fiix Body is rated higher. Katalyst averages 4.6 out of 5 from 59 ratings, while Fiix Body averages 4.7 from 298 ratings.

### Do Katalyst or Fiix Body have ads?

Neither Katalyst nor Fiix Body shows ads.

### Which is updated more often, Katalyst or Fiix Body?

Katalyst ships an update every 3 weeks, and Fiix Body every 5 weeks. Most recently, Katalyst was updated on October 25, 2026 and Fiix Body on October 24, 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.*