Privacy policy

Last updated November 5, 2026

Lysine is a nutrition diary for tracking the lysine-to-arginine ratio of what you eat. It is provided by Living Contrast (“we”, “us”). This policy explains what information the Lysine app and website collect, why, who we share it with, and the choices you have. Some of what you can record, such as outbreak logs, is health information, and we treat it with extra care.

The short version

We collect what you enter and what we need to run your account. Nothing more.
We don’t sell your information, show ads, or use advertising or analytics trackers.
Your health entries are never put in push notifications, emails or our server logs on purpose.
You can delete your account and everything in it at any time, in the app or on the website. Here’s how.

What we collect

Account information

Your email address and, if you give one, your name.
Your password, stored only as a secure one-way hash. If you sign in with Apple or Google, we receive your email address (or Apple’s private relay address), your name if you choose to share it, and an account identifier from them. We never see your Apple or Google password.
Your settings: ratio thresholds, notification preferences and time zone.

What you record

Meals and the foods and amounts in them, lysine supplements, recipes, ratings and favorites.
Health information you choose to add: outbreak logs and check-ins (dates, symptoms, severity, notes), symptom logs, and whether you’re tracking because of HSV. This is optional. The app works for nutrition tracking without it.
Recipe photos you upload.

Recipes are private unless you choose to share one publicly. A public recipe is reviewed and then visible to other users, with your name as its author.

Purchases

If you buy from the shop, payment is handled by Stripe. We keep an order record (what you bought, the amount, status and Stripe’s reference numbers). We never receive or store your card details.

Device and technical information

For the mobile app: a push notification token, the device’s name and platform (to show your signed-in devices) and sign-in session tokens, stored securely on your device.
Our hosting provider records standard request logs (such as IP address, time and the page or API called) to keep the service running and secure.

How we use it

To run your account: show your ratio, history, trends and insights, and keep your data in sync between the app and the website.
To show outbreak insights, which compare your own outbreak logs with your nutrition history. These are correlations from your own data, not medical findings.
To send notifications you can turn off, such as a ratio warning after a meal or an order update.
To send sign-in emails and messages about your account or purchases.
To keep the service secure, fix problems and prevent abuse.

We don’t use your information for advertising, we don’t sell or rent it, and we don’t use your health entries for anything other than showing them back to you.

Who we share it with

We share information only with service providers that run parts of Lysine for us, under contracts that limit their use of it to providing that service:

Vercel hosts the website and API.
Neon hosts our database.
Cloudflare or Amazon Web Services store uploaded recipe photos.
Resend sends sign-in and account emails.
Stripe processes shop payments.
Expo and Apple or Google deliver push notifications to your device. Notification text never includes health details.
Apple and Google verify your identity if you use their sign-in.

Food values come from USDA FoodData Central, a public database. We don’t send it anything about you. We may also disclose information if the law requires it, or to protect the safety of our users or others.

How long we keep it

We keep your information while your account exists. When you delete your account, we delete it right away: your profile, entries, recipes, photos, devices and order records. Database backups that may still contain it are overwritten within 30 days. Stripe keeps its own payment records as the law requires.

Your choices and rights

Edit or delete entries at any time in the app or on the website.
Delete your account in the app (Profile → Settings → Delete my account) or on the website (Profile → Settings). See Delete your account, which also explains how to ask us by email if you can’t sign in.
Turn off notifications in the app’s settings or your phone’s settings.
Get a copy of your data, or correct it, by emailing us. Depending on where you live, you may have further rights over your information. Write to us and we’ll respond as the law requires.

Security

Information is encrypted in transit, passwords are hashed, and sign-in tokens on your phone are kept in its secure storage. Access to our systems is limited to what’s needed to run the service. No system is perfectly secure, but we work to protect your information and will tell you if a breach affects it.

Age

Lysine is for people 18 and older. We don’t knowingly collect information from anyone younger. If you think someone under 18 has an account, contact us and we’ll delete it.

Changes

If we change this policy in a meaningful way, we’ll update the date above and tell you in the app or by email before the change takes effect.

Contact

Questions or requests about your information: support@lysine.app.