Comparison

KetoAir vs Function Health

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

KetoAir

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
Read full description

KetoAir is a breathlayzer that provides accurate and instant results in just a single blow. KetoAir Breathlayzer: •Accurate, real acetone sensor •Quick and easy - Just a single blow, get the result in seconds •Test anytime and anywhere •Keep yourself monitored and motivated, helping you to sustain your perseverance KetoAir App: •Log your ketosis record •Connect the device via Bluetooth Introducing the KetoAir Breathalyzer - the perfect tool for health and wellness conscious individuals who are looking to optimize their ketosis state and body fat burning rate! This pocket-sized breathalyzer provides accurate and instant results in just a single blow, giving you the ability to monitor how different foods affect your ketone level. By measuring the level of acetone in your breath, which is produced by the liver during the process of ketone energy formation, you can determine your body's fat burning status and adjust your diet accordingly. Without pain, you can test your ketone levels anytime and anywhere, keeping yourself motivated to reach your optimal ketosis state and fat burning rate. Plus, breath acetone levels can be influenced by certain body measurements, such as body composition and exercise, giving you even more insight into your overall health and wellness. No more guessing on your body's fat burning potential. Take control of your health and wellness with the KetoAir Breathalyzer. Check out the weight management reference article to learn more about how breath acetone and body measurements are related and how you can optimize your ketosis state for maximum fat burning potential. Disclaimer: Always seek a doctor’s advice in addition to using this app and before making any medical decisions. The KetoAir device has registered with the U.S. Food and Drug Administration as Class 1 medical device. Weight management reference article: https://onlinelibrary.wiley.com/share/7GUVTR5WWPWNCY9KPIYE?target=10.1002/oby.21242

About

Function Health

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
Read full description

Function membership helps you take control of your health with 160+ lab tests each year, personalized Protocols, and Private AI Chat powered by Medical Intelligence—all backed by advanced science and your real data. Built with top doctors, Function gives you the power to understand your body, track how it evolves, and make meaningful change. NOW AVAILABLE: HOME OR OFFICE BLOOD DRAWS Schedule a concierge blood draw at your home or office. A licensed specialist comes to you and completes your blood draw in under 20 minutes. Available in select locations. 160+ LAB TESTS Membership includes testing for your heart, hormones, thyroid, liver, kidneys, toxins, nutrients, inflammation, autoimmunity, immunity and more. ADVANCED MRI & CT SCANS Detect early signs of cancer and hundreds of other potential conditions with the option to purchase advanced imaging for your brain, pancreas, liver, spine, ovaries, prostate, heart and much more. MEDICAL INTELLIGENCE Built with leading medical scientists, Function’s proprietary model brings together your health history and insights from a large population to help you better understand your health and find steps you can take today to support your health over time. PRIVATE AI CHAT Ask questions about your results, identify meaningful patterns, and figure out where to focus next, with Private AI Chat—powered by Medical Intelligence and built in partnership with top clinicians. CONNECT WEARABLES Connect Apple Health and other health devices and wearables to see how your activity, sleep, and daily habits affect your lab test results and long-term health. PROTOCOLS Translate your lab results, scans and health history into clear, evidence-based plans for nutrition, activity, and supplements—all customizable to your goals and preferences. UPLOAD HEALTH RECORDS Upload past lab test results, scans, and other medical records for a more complete view of your health, all in one secure place. PROGRESS YOU CAN SEE Twice-yearly and On-Demand testing helps you track your results over time, monitor for early signs of disease, and identify where to focus next. ADVANCED LAB TESTS Membership includes 160+ lab tests, plus the option to purchase advanced On-Demand tests for: - Detection of 50+ cancers - Alzheimer’s risk detection - MTHFR gene variants - Advanced MRI and CT scans starting at $365 - Food allergies and sensitivities - …and much more ACCESSIBILITY What could cost as much as $15,000 on your own is included with membership for just $365/year. Lab testing is available at over 2,000 lab locations across the US, with no insurance needed. SECURITY Function was built for privacy and security. Function is built to HIPAA standards. Your information is secure. How it works: 1. Join Function and schedule your first set of lab tests. 2. Get your results and personalized Protocols. Ask questions with your Private AI Chat. 3. See your progress with 60+ lab tests at your Mid-Year Test. 4. Purchase MRI or CT scans and other advanced On-Demand Tests any time. DISCLAIMER Function Health is a technology company and not a laboratory or medical provider. All laboratory and medical services are provided by independent third parties. Function Health does not offer medical advice, laboratory services, a diagnosis, medical treatment, or any form of a medical opinion; its services are not a substitute for medical care, medical advice, and/or a detailed discussion with a physician or other licensed provider. If you have any questions regarding any laboratory results or any other information that you access through Function Health, you should contact a physician or other licensed provider. All material, information, data, and content that Function Health provides is strictly for general information purposes. For additional important information: https:// www.functionhealth.com/terms-of-service.

Screenshots

KetoAir4 screens
Function Health4 screens

Verdict

The call

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.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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

Scorecard5 real differences · 5 level
KetoAir versus Function Health: the parameters behind the verdict, then further details
ParameterKetoAirFunction Health
PriceFreeFree
Rating1.5 (2 ratings)4.9 (25K ratings) — better
Positive reviews—61.5% of reviews
Number of ratings225K — better
Update frequencyEvery 2 monthsWeekly — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterSubscription
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS16.416.4
Further details — not scored
Size60 MB205 MB
Age rating4+17+
DeveloperQi Diagnostics LimitedFunction Health

Customer experience

KetoAir

All ratings1 ratings
Positive0.0%
Neutral0.0%
Negative100.0%

Function Health

All ratings25,084 ratings
Positive99.0%
Neutral0.4%
Negative0.6%
Written reviews351 reviews
Positive61.5%
Neutral5.7%
Negative32.8%

Bugs and requests

KetoAir

Not enough reviews yet to summarise bugs or requests.

Function Health

Reported bugs

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

Requested features

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

In-app purchases

None

KetoAir

No in-app purchases

None

Function Health

No in-app purchases

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.

Other comparisons