Privacy Policy

Effective date: June 19, 2026

This Privacy Policy explains how Tirzing ("Tirzing", "we", "us", or "our") collects, uses, and shares information when you use our website, applications, and related services (the "Service"). By using the Service, you agree to the practices described here.

The short version

Optional AI features may send anonymized data to third-party AI providers to deliver AI assistance.
Your anonymized weight data may be used to make our prediction models more accurate.
We do not sell your personal data.

1. Information we collect

Account information: your name, email address, and password (stored hashed).
Health and tracking data: information you choose to log, such as weight, medications, doses, shots, supply/vials, side effects, mood, energy, sleep, and notes.
Payment information: handled by our payment processor (Stripe). We receive limited billing and subscription status details but do not store your full card number.
Usage and device data: basic technical information such as IP address, browser type, and log data used to operate and secure the Service.

2. How we use your information

To provide, maintain, and improve the Service and its features;
To generate your estimates, predictions, progress views, and insights;
To process subscriptions and payments;
To communicate with you about your account, security, and updates;
To protect the Service, prevent abuse, and comply with legal obligations.

3. AI features and third-party AI providers

Some optional features of the Service use artificial intelligence to generate summaries, narratives, or other assistance. When you use these features, we may send anonymized data, stripped of information that directly identifies you, to third-party AI providers so they can process it and return a result. These providers process the data on our behalf to deliver the requested AI assistance.

4. Anonymized data and our prediction models

We use anonymized weight data, along with other anonymized, aggregated tracking data, to develop and improve the accuracy of our prediction models, such as supply runway, medication-level estimates, and weight-vs-peers comparisons. Anonymized and aggregated data cannot reasonably be used to identify you, and we may retain and use it even after individual records are deleted.

5. We do not sell your personal data

We do not sell your personal data, and we do not share your identifiable health data with advertisers. We only share information as described in this Policy.

6. How we share information

We share information only in these limited circumstances:

Service providers: vendors who help us operate the Service, such as our payment processor (Stripe), email/delivery providers, hosting, and the third-party AI providers described above, each acting on our instructions.
Anonymized / aggregated data: as described in Sections 3 and 4.
Legal and safety: when required by law, to enforce our Terms, or to protect the rights, safety, and security of our users or the Service.
Business transfers: in connection with a merger, acquisition, or sale of assets, subject to this Policy.

7. Data retention

We retain your personal data for as long as your account is active or as needed to provide the Service and meet legal obligations. You can delete your account, after which we will delete or anonymize your personal data within a reasonable period, except where retention is required by law. Anonymized and aggregated data may be retained as described above.

8. Security

We use reasonable technical and organizational measures to protect your information, including encryption in transit and hashed passwords. No method of transmission or storage is completely secure, and we cannot guarantee absolute security.

9. Your rights and choices

Access, update, or correct your information from within the Service;
Delete your account and associated personal data;
Opt out of optional AI features by not using them;
Depending on your location, you may have additional rights (such as access, portability, or objection). Contact us to exercise them.

10. Children

The Service is not directed to anyone under 18, and we do not knowingly collect personal data from children. If you believe a child has provided us information, please contact us.

11. Changes to this Policy

We may update this Privacy Policy from time to time. If we make material changes, we will take reasonable steps to notify you. The "Effective date" above indicates when this Policy was last revised.

12. Contact

Questions about this Policy or your data? Contact us at privacy@tirzing.com.