# KetoAir vs Function Health

The clearest difference is rating: Function Health at 4.9 against KetoAir's 1.5. Function Health also leads on update cadence (weekly vs every 2 months) and ratings volume (25K vs 2). KetoAir's advantage is monetization model (free vs subscription) and device support (3 vs 1). On price, ads, in-app purchases and iOS requirement there is nothing between them.

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

Function Health holds the better App Store score, 4.9 against 1.5. That said, the two scores are not equally well evidenced: Function Health has 25K ratings behind it against 2, so its average is the more settled of the two.

KetoAir ships an update every 2 months, Function Health weekly. The most recent releases landed on October 6, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | KetoAir | Function Health |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.5 (2 ratings)](https://appshunter.io/ios/app/ketoair/id1671355214/reviews) | **[4.9 (25K ratings)](https://appshunter.io/ios/app/function-health/id6471280307/reviews)** |
| Number of ratings | 2 | **25K** |
| Positive reviews | — | 61.5% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Weekly** |
| Monetization | **Free** | Subscription |
| Size | 60 MB | 205 MB |
| Requires iOS | 16.4 | 16.4 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 17+ |
| Developer | [Qi Diagnostics Limited](https://appshunter.io/developer/1636454031) | [Function Health](https://appshunter.io/developer/1715014524) |

## What reviewers say

### KetoAir

[App page](https://appshunter.io/ios/app/ketoair/id1671355214)

This device and companion app help you monitor your body's fat-burning status by measuring acetone levels in your breath. Get instant, accurate results to understand how your diet and exercise affect your ketosis.

**Highlights:** Instant breath acetone measurement, Accurate real acetone sensor, Bluetooth device connectivity, Log ketosis records, Monitor fat-burning status, Track diet and exercise impact

**Features:** macOS Compatibility

**In-app purchases:** none


### Function Health

[App page](https://appshunter.io/ios/app/function-health/id6471280307)

Take control of your health with comprehensive lab testing, personalized protocols, and AI-powered insights. Understand your body's data, track changes over time, and make informed decisions for long-term wellness. Connect wearables and upload records for a complete health picture.

**Highlights:** 160+ lab tests annually, Personalized health protocols, Private AI Chat for results, Connect health wearables, Advanced MRI & CT scans, Upload health records

**Features:** Apple Wallet

**In-app purchases:** none

**What reviewers like**

- 🚀 Seamless process for blood tests and results
- 📊 Comprehensive health insights and tracking
- 🧠 Helpful clinician notes and recommendations
- 👍 User-friendly and visually appealing app
- 💰 Affordable compared to other options

**What reviewers complain about**

- 🔍 Lack of communication and support responsiveness
- 🐛 Some bugs and usability issues in the app

**Reported bugs**

- App sometimes redirects back to the home screen when trying to view results
- Occasional typos and formatting issues in the app

**Requested features**

- More customization options in the app settings
- Ability to print or export test results and recommendations
- Specific supplement recommendations rather than broad suggestions


## Frequently asked questions

### Is KetoAir free?

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

### Is Function Health free?

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

### Which has better reviews, KetoAir or Function Health?

Function Health is rated higher. KetoAir averages 1.5 out of 5 from 2 ratings, while Function Health averages 4.9 from 25K ratings.

### Do KetoAir or Function Health have ads?

Neither KetoAir nor Function Health shows ads.

### Which is updated more often, KetoAir or Function Health?

KetoAir ships an update every 2 months, and Function Health weekly. Most recently, KetoAir was updated on October 6, 2026 and Function Health 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.*