Privacy Policy
Last updated: April 23, 2026
MuscleGuard ("we", "us", "the app") is designed to keep the information you record about your body and medication on your iPhone, not on our servers. We do not operate user accounts. We do not sell data. We do not run advertising networks inside the app.
1. What stays on your device
The following data is stored only in MuscleGuard's local database on your iPhone, protected by Apple file protection:
- Profile details, including age, sex, height, starting and goal weight, activity level, kidney-disease flag, medication brand, and dose
- Weight entries, DEXA or InBody scans, food entries, progress photos, strength sessions, injections, and side-effect logs
- Any PDFs, images, or notes you choose to import
- Your Muscle Signals check-in answers
We never upload this data to our servers. It does not leave your device unless you explicitly tap Share, Export, or one of the AI Analyze actions described below.
2. Optional AI features
Some features are powered by an AI model hosted by OpenAI. When you explicitly tap one of these actions, the relevant input is transmitted over an encrypted HTTPS connection through our Cloudflare Worker proxy to OpenAI, and the returned result is shown to you:
- Analyze food photo: the photo is sent for nutrition estimation
- Extract DEXA or InBody report: OCR text from the scan is sent for structured extraction
- Trend Snapshot PDF summary: aggregated numeric summaries without identifiers are sent to generate a short plain-language summary
Our proxy strips identifiers before forwarding. We do not attach your name, email, device ID, or IP address to these requests. We do not log the content. OpenAI processes these API requests under its API data-processing terms and does not use them to train its models.
If you never tap those buttons, no photo, scan, or summary ever leaves your device.
3. On-device analysis
Progress photo face-proportion analysis runs entirely on your iPhone using Apple's Vision framework. Your progress photos never leave your device.
4. Apple Health
With your permission, MuscleGuard reads weight, lean body mass, body fat percentage, and strength-workout data from Apple Health. This access is governed by iOS. You can revoke it at any time in Settings > Privacy & Security > Health > MuscleGuard. MuscleGuard does not write to Apple Health unless you explicitly tap a save action.
5. Purchases
Subscriptions are processed by Apple through the App Store. We receive only the information Apple provides to developers, such as whether a subscription is active, expired, or in trial, plus the product ID. We do not receive your payment details.
6. Crash reports and analytics
MuscleGuard does not integrate any third-party crash reporter, analytics SDK, tracking pixel, or ad network. The app uses Apple's optional crash reporting system if you enable it in iOS settings. That data goes to Apple, not to us.
7. Children
MuscleGuard is not intended for anyone under 18. We do not knowingly collect any data from minors.
8. Your controls
- Delete any entry from inside the app
- Delete the app to wipe all local data
- Disable Apple Health access in iOS settings
- Cancel your subscription at any time in Settings > Subscriptions
9. Contact
Privacy questions: privacy@muscleguard.app
Support: support@muscleguard.app
10. Changes
If we change this policy, we will update the "Last updated" date above and publish the new version in-app and on this page.