Privacy Policy & Terms of Service

Last Updated: May 20, 2026

Privacy Policy

40Hz Gamma is built with a "Privacy by Design" approach. Our core principle is that your data belongs to you.

  • Data Collection (Zero Collection): We do not collect, store, or transmit any personal information, usage data, device identifiers, or biometric information. This app is 100% offline-functional.
  • No Analytics: We do not use any third-party tracking tools, cookies, or analytics services (e.g., Firebase, Facebook SDK).
  • No Advertising: This app is pure and ad-free. We do not share any data with advertising networks.
  • In-App Purchases and Subscriptions: 40Hz Gamma offers in-app purchases and auto-renewable subscriptions to unlock premium features. All financial transactions and payment data are processed securely by Google Play (or third-party payment gateways like Stripe for independent distribution). The developer does not collect, access, or store your credit card numbers or financial information.
  • Data Security: Since no data is collected or transmitted to external servers, there is no risk of data breaches from our side. Any settings you save remain encrypted within your local device storage.
  • Contact Information: If you have any questions regarding privacy, you can reach us at: xiuyinlin644@gmail.com or jie.cai2@gmail.com.

Terms of Service

Welcome to 40Hz Gamma. Please read the following terms carefully before using the app:

  • Medical Disclaimer & Safety Warning:

    ⚠️ PHOTOSENSITIVE EPILEPSY WARNING:

    This app contains visual stimulation with 40Hz flashing lights. Do not use this application if you have a history of seizures, epilepsy, or photosensitivity. Discontinue use immediately and consult a doctor if you experience dizziness, altered vision, eye or muscle twitches, loss of awareness, disorientation, or any involuntary movement.

    Non-Medical Device: This app is intended for wellness and general cognitive research purposes only. It is not a medical device, and is not intended to diagnose, treat, cure, or prevent any disease. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

  • App Usage: The app is intended for personal, non-commercial use. You agree to use the app only for its intended purpose.
  • Subscriptions & Purchases: We offer premium features via subscriptions (Android) or one-time purchases (iOS). Android subscriptions are managed through the Google Play Store.

    Subscription Renewal: Your subscription will automatically renew at the end of each billing period unless cancelled at least 24 hours before the renewal date.

    Refund Policy: Subscriptions purchased via Google Play are subject to Google Play’s refund policies. Standalone purchases are final and non-refundable unless otherwise specified.

  • Intellectual Property: The app and all its content are protected by copyright and intellectual property laws and are the property of 40Hz Gamma and its licensors.
  • Changes: We reserve the right to modify or update these terms at any time. Continued use signifies acceptance of changes.