# Cafactor vs Sthenos

The clearest difference is price: Cafactor at Free against Sthenos's $3.99. Sthenos's advantage is in-app purchases (none vs 1). On update cadence, ads, device support and iOS requirement there is nothing between them.

Cafactor is free to download; Sthenos costs $3.99 up front. Cafactor sells 1 one-off in-app purchase. Sthenos asks for nothing beyond the download.

Cafactor ships an update weekly, Sthenos every 11 days. The most recent releases landed on September 25, 2026 and October 4, 2026 respectively.

## The numbers

| Metric | Cafactor | Sthenos |
| --- | --- | --- |
| Price | **Free** | $3.99 |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/cafactor/id6757445668/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Weekly** | Every 11 days |
| Monetization | Freemium | — |
| Size | 9 MB | 5 MB |
| Requires iOS | **17.6** | 18.0 |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [Nan Yu](https://appshunter.io/developer/1559044036) | [Georgios Stavropoulos](https://appshunter.io/developer/1792154671) |

## What reviewers say

### Cafactor

[App page](https://appshunter.io/ios/app/cafactor/id6757445668)

This app models your body's real-time caffeine levels using a scientific pharmacokinetic approach. It helps you understand your caffeine absorption, decay, and personal sleep thresholds, adapting to your unique biology and activity. Connect with health data for an even smarter metabolic coaching experience.

**Highlights:** Real-time caffeine curve modeling, Personalized physiological parameters, HealthKit integration for adaptive coaching, Exercise and sleep-adaptive thresholds, HRV & Recovery integration, Progressive calibration of half-life, Offline, private tracking

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Cafactor Pro | $3.99 | one-time |


### Sthenos

[App page](https://appshunter.io/ios/app/sthenos/id6760965966)

**Features:** Apple Watch app

**In-app purchases:** none


## Frequently asked questions

### Is Cafactor free?

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

### Is Sthenos free?

Sthenos costs $3.99, with no in-app purchases.

### Do Cafactor or Sthenos have ads?

Neither Cafactor nor Sthenos shows ads.

### Which is updated more often, Cafactor or Sthenos?

Cafactor ships an update weekly, and Sthenos every 11 days. Most recently, Cafactor was updated on September 25, 2026 and Sthenos on October 4, 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.*