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Key to Health: Metabolic AI

Key to Health: Metabolic AI

Your metabolism, optimized

2.3K ratings
143 reviews
💪 Health & Fitness
Free
In-App Purchases

Details

  • Released
  • Updated
  • February 8, 2019
  • August 6, 2026

Developer

Keyto, Inc.
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About

Understand your body's fat metabolism in real-time with a connected breath sensor. Receive personalized AI coaching to optimize your health, track progress, and build strength without restrictive diets. Achieve your wellness goals with science-backed guidance.

✓Real-time fat metabolism tracking
✓AI health coaching
✓Personalized goals and progress tracking
✓Strength building tools
✓No restricted foods or diets
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What users say

Summarized from real user reviews of Key to Health. Based on 2.3K reviews and a 4.8/5 average, it highlights the 6 positives and 6 negatives reviewers mention most about this Health & Fitness app.

Positive things

  • 🚀Easy to use
  • 👍Accurate ketone readings
  • 🚀Convenient and portable
  • 👍Helpful for staying on track with keto
  • 👍Motivating and informative app
  • 🚀Simple and straightforward

Negative things

  • 🐛Connectivity issues
  • 🐛Inconsistent readings
  • 💰Expensive subscription
  • 🔍Limited food database
  • 🐛Buggy app updates
  • 🔍Lack of customization options
See all reviews
+1

What's New in Key to Health

4.0.5

August 6, 2026

• Bug fixes and performance improvements

Subscription plans

Keyto Annual Subscription

Keyto Annual Subscription

$95.991 Year
14 Days trial
How to cancel Key to Health subscription ⁉️

User reviews

Most RecentHighest RatedLowest Rated

Great device and app

Really love this device and app. I wish you’d make a change to the age ratings. It’s on 18+ now so I cannot use it on my phone. Don’t see why this needs to be 18+. Even 16+ would be very conservative.
Harbinger613Harbinger613

Great but…

This a great little device to measure ketosis. However the app has this fire sound effect after taking measurements that is SO LOUD. I’m trying to take measurements in the beginning of the day upon first waking up, but there’s no way to turn this sound fx off. There is no option to turn it off in the app settings or in apple’s settings. It does not even respond to the volume setting! I should be able to take my measurements without waking other people up. Please allow the option to silence it!
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Little_BirdoLittle_Birdo

New design is magic

I have been using Keyto on and off for many years with great results. The new design is super. It was a much needed refresh and it delivers. Excellent product.
acrobat-sfacrobat-sf

Don’t Bother

This is a scam…I can no longer use my Keyto because they decided to charge $50 a month to use the app. This was free.
Don’t Buy KeytoDon’t Buy Keyto

Trends

I don’t have a subscription, so maybe that is why every single day it shows that I it is my first time blowing. It doesn’t show my trend.
I am Linda YoungI am Linda Young
See 138 more reviews

User experience

🐞

Reported Bugs

4 issues

App crashes when reaching 100% during measurement

Bug

Inconsistent connectivity between device and app

Bug

Incorrect weight display in metric units

Bug

App stuck in loop during onboarding process

Bug
✨

Requested Features

4 requests

Add ability to edit or delete recorded readings

Feature

Integrate with Apple Health or other fitness apps

Feature

Expand food database, especially for non-US users

Feature

Provide more personalized coaching and feedback

Feature

FAQ

What does Key to Health: Metabolic AI do?

This app helps you understand your body's fat metabolism in real-time using a connected breath sensor. It provides personalized coaching from an AI guide to optimize your health, track progress, and build strength without requiring restrictive diets or forbidden foods.

What are the key features of this app?

Key features include real-time fat metabolism tracking via a breath acetone sensor, personalized coaching from an AI health guide named KEY, clear science-based goals, progress tracking, and tools to build strength. It emphasizes eating what you love without needing keto or restricted foods.

How much does Key to Health: Metabolic AI cost?

The app offers a monthly subscription at $49.99/month for unlimited access to premium features. Payments are charged to your Apple Account and subscriptions automatically renew unless turned off at least 24 hours before the current period ends.

Who is this app designed for?

This app and its accompanying breath monitor are designed for adults aged 18 and older, particularly high-achieving, busy individuals who want to improve their appearance, well-being, and long-term health without complex or time-consuming routines.

Can I use this app without a breath sensor?

The core functionality of real-time fat metabolism tracking relies on the connected breath acetone sensor. While the AI coaching and progress tracking features may offer some utility independently, the primary benefit of understanding your metabolism is tied to the sensor's data.