Legal

Privacy Policy

Last updated: August 4, 2026

Who we are

Stackr is operated by Stackr Holdings LLC, a New Jersey limited liability company with a registered address at 62 Boyce Place, Ridgewood, NJ 07450, United States. Stackr Holdings LLC is the data controller for personal information processed through the Stackr app and this website.

Summary

Stackr is a personal tracking app for peptides. Your data — peptides, doses, supplies, side effects, body metrics — is yours. We do not sell it, share it with advertisers, or use it to train AI models. We do run ads to find new users, and we measure which of those ads work. That measurement never involves anything you log. See Advertising measurement below for exactly what is sent and how to switch it off.

What we collect

  • Account data. If you sign in, we store your email and a Stackr user ID so we can sync your data across your devices.
  • Tracking data. Anything you log inside the app — peptides, doses, vials, body metrics, notes — is stored on your device and, if you sign in, in your private account in our database.
  • Progress photos. If you add before/after photos, they are stored on your device and, if you are signed in, backed up to your private account so they survive a reinstall or a new phone. They are held in a private storage bucket, encrypted at rest, and access is restricted to your own account — no other user can reach them. They are never shown publicly, never shared, and never used for advertising or to train AI models. Deleting a photo in the app deletes it from our storage as well.
  • Analytics. Anonymous app usage events (e.g. "dose logged", "paywall viewed") via Mixpanel, keyed to a per-user identifier we generate. Never tied to your email or content of your logs.
  • Subscription state. Apple tells us whether you have an active Stackr+ subscription. We never see your payment details.
  • Advertising measurement. We buy ads to reach new people, and we need to know which ads actually work. Your iPhone carries an advertising identifier, a random number that ad platforms use to recognise a device. If you allow tracking when iOS asks, Stackr sends that identifier, your IP address, and the fact that an install or a subscription happened to AppsFlyer, our measurement provider, which passes it on to advertising platforms including Meta. Under Apple’s definition this counts as tracking, so we say so plainly. Nothing you log is ever included: no peptides, doses, supplies, side effects, body metrics, notes, or photos. If you decline the prompt, no advertising identifier is sent. You can change your mind at any time in iOS Settings under Privacy & Security → Tracking.

What we don't do

  • We don't sell your data.
  • We don't share anything you log with advertisers. Not your peptides, doses, supplies, side effects, body metrics, notes, or photos.
  • We don't use it to train AI models.
  • We don't read your logs to target ads at you, and we don't build a profile of your health. The only thing our ad measurement sees is a device identifier and whether an install or purchase happened, and only if you allow tracking when iOS asks.

Emails we send

We use your email address to run your account: sign-in, security notices, receipts, and support replies. We may also send occasional messages about Stackr itself, such as new features, tips for getting more out of tracking, and offers. Every one of those carries an unsubscribe link, and opting out never affects your account or anything you have logged. Account and security emails are not marketing and are always sent. We do not sell or rent your email address, and we do not share it with advertisers.

Deleting your data

You can delete your account at any time from Settings → Data → Delete account inside the Stackr app. Deletion is immediate on our servers when you tap it; if your device is offline at the moment of deletion, the request is queued and completes once you reconnect (always within 14 days).

Contact

Questions about this policy or your data? Reach Stackr Holdings LLC at support@stackrpeptides.com.