Privacy Policy

How we protect and handle your personal information.

Last updated: October 2026

Our Commitment to Your Privacy

At Four Integers Ltd, we understand that your health data is deeply personal. This Privacy Policy explains how we collect, use, protect, and share your information when you use Gut Lens.

By using our app, you agree to the collection and use of information in accordance with this policy.

Information We Collect

Health and Symptom Data

We collect what you log in the app: your daily check-ins, symptoms, bowel logs, meals and meal photos, the foods you test and your results, your Calm Gut progress, and the answers you give during setup. This data is essential for running your plan and providing AI analysis.

Account Information

We collect your email address and any profile information you choose to provide when creating an account. If you sign in with Apple or Google, we receive the basic account details they share with us.

Voice Recordings and Photos

When you log by voice, or scan a meal or a menu, the recording or photo is sent to our servers so it can be analyzed and turned into a log.

What Fern Remembers

Fern, the in-app guide, keeps short notes about you so her messages fit your situation, including anything you choose to tell her. You can see these notes in the app, forget any of them, or turn personalization off.

Usage and Diagnostic Data

We collect information about how you use the app, including features accessed, along with crash reports, to fix problems and improve our services.

Location Data

When you use the toilet finder, your location is used to look up nearby public toilets from a third-party directory. We do not store your location.

Notifications and Purchases

If you turn on reminders, we store a notification token and your time zone so we can send them. Subscriptions are handled by the App Store or Google Play. We receive your subscription status, not your payment details.

How We Use Your Information

Your Health Data Stays Private

We never sell, rent, or share your personal health information with third parties for marketing purposes.

  • Provide Services: Run your trigger plan, analyze your meals and menus, and work out your results
  • Personalization: Tailor Fern’s notes, meal plans and recommendations to your triggers and patterns
  • Improve Our App: Understand how features are used to make improvements
  • Communication: Send the reminders you choose and important updates about the app or your account
  • Support: Help you with questions or technical issues

Data Security

We implement industry-standard security measures to protect your data:

  • All data is encrypted in transit and at rest
  • Secure cloud infrastructure with regular security audits
  • Limited access to personal data on a need-to-know basis
  • Regular security updates and monitoring

Data Sharing

We only share your data in the following limited circumstances:

  • With Your Consent: When you explicitly agree to share specific information
  • Service Providers: With trusted third-parties who help us operate the app, such as cloud hosting, AI analysis, analytics, crash reporting, notifications and subscription management (under strict confidentiality agreements)
  • Legal Requirements: When required by law or to protect our rights and safety
  • Anonymized Data: We may use aggregated, anonymized data for research to improve IBS understanding

The service providers we currently use are:

  • Supabase: Stores your account, your logs and your meal photos
  • OpenAI: Analyzes meal photos, menus, voice recordings and text for the app’s AI features
  • Mixpanel: Usage analytics
  • Sentry: Crash reports
  • RevenueCat: Subscription status
  • Expo: Delivers push notifications
  • Refuge Restrooms: Toilet finder directory, which receives your location directly from your device when you search

Some of these providers may process your data outside the United Kingdom, including in the United States.

Your Rights

You have the following rights regarding your data:

  • Access: Request a copy of your personal data
  • Correction: Update or correct inaccurate information
  • Deletion: Request deletion of your account and data
  • Portability: Export your data in a common format
  • Opt-out: Unsubscribe from communications at any time

To exercise these rights, contact us at hello@fourintegers.com.

Data Retention

We retain your data only as long as necessary to provide our services or as required by law. When you delete your account in the app, your account, logs, meal photos, results and plan are deleted straight away, except for anonymized usage statistics that help us improve the app.

Children’s Privacy

Gut Lens is not intended for children under 13. We do not knowingly collect personal information from children under 13. If you believe we have collected such information, please contact us immediately.

Updates to This Policy

We may update this Privacy Policy from time to time. We will notify you of any changes by posting the new policy on this page and updating the "Last updated" date. Continued use of the app after changes constitutes acceptance of the updated policy.

Contact Us

If you have questions about this Privacy Policy or how we handle your data, please contact us:

Email: hello@fourintegers.com

Company: Four Integers Ltd