# 40 Day Challenge vs Zystem.One

The clearest difference is review sentiment: Zystem.One at 100% against 40 Day Challenge's 0%. Zystem.One also leads on rating (5.0 vs 1.0). 40 Day Challenge's advantage is iOS requirement (13.4 vs 15.5). On price, ratings volume, 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.

Zystem.One holds the better App Store score, 5.0 against 1.0. Both are backed by a comparable volume of ratings — 1 and 2 respectively. Written reviews point the same way: 0% of 40 Day Challenge's written reviews are positive against 100% of Zystem.One's.

40 Day Challenge ships an update every 6 weeks, Zystem.One monthly. The most recent releases landed on November 6, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | 40 Day Challenge | Zystem.One |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.0 (1 ratings)](https://appshunter.io/ios/app/40-day-challenge/id1351860748/reviews) | **[5.0 (2 ratings)](https://appshunter.io/ios/app/zystemone/id6768262331/reviews)** |
| Number of ratings | 1 | **2** |
| Positive reviews | 0.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 6 weeks | **Monthly** |
| Monetization | Free | Free |
| Size | 25 MB | 144 MB |
| Requires iOS | **13.4** | 15.5 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 12+ | 4+ |
| Developer | [FITFIRM GmbH](https://appshunter.io/developer/1351860747) | [nutrilize GmbH](https://appshunter.io/developer/1521442832) |

## What reviewers say

### 40 Day Challenge

[App page](https://appshunter.io/ios/app/40-day-challenge/id1351860748)

This app helps users achieve personal goals through motivational techniques, audios, and videos. It incorporates features from positive psychology and mindfulness to improve life quality and offers daily goal tracking with configurable reminders.

**Highlights:** Collect points to track progress, Positive psychology techniques, Mindfulness audio tutorials, Video introductions to personal development areas, Daily goal tracking and reflection, Configurable reminders

**Features:** macOS Compatibility

**In-app purchases:** none


### Zystem.One

[App page](https://appshunter.io/ios/app/zystemone/id6768262331)

This app provides personalized online coaching for a healthier lifestyle. It includes features for food tracking, custom meal plans, workout routines, progress monitoring, and direct chat with your coach. It also syncs with Apple Health to help you achieve your wellness goals.

**Highlights:** Food tracking and recipes, Individual nutrition plans, Workout plans and tracking, Progress monitoring, Apple Health synchronization, Direct coach chat

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

**In-app purchases:** none


## Frequently asked questions

### Is 40 Day Challenge free?

40 Day Challenge is free to download, with no in-app purchases.

### Is Zystem.One free?

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

### Which has better reviews, 40 Day Challenge or Zystem.One?

Zystem.One is rated higher. 40 Day Challenge averages 1.0 out of 5 from 1 ratings, while Zystem.One averages 5.0 from 2 ratings.

### Do 40 Day Challenge or Zystem.One have ads?

Neither 40 Day Challenge nor Zystem.One shows ads.

### Which is updated more often, 40 Day Challenge or Zystem.One?

40 Day Challenge ships an update every 6 weeks, and Zystem.One monthly. Most recently, 40 Day Challenge was updated on November 6, 2026 and Zystem.One 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.*