Privacy policy
The short version
- Your logs stay on your phone. Periods, symptoms, moods, sex, tests, temperatures, notes and your health profile are stored only in Luna on your device. We don’t have them.
- No account, no ads, no analytics, no tracking. We never sell or share your data.
- Ask Luna is optional. If you turn it on, your question and a short cycle summary are sent to an AI service to write the answer. Never your name or your full logs.
- You’re in control. Back up, export or delete everything from Settings at any time.
1. Who we are
Luna is a period and cycle tracking app for iPhone and Android. In this policy, “Luna”, “we” and “us” mean the developer of the app. You can contact us at support@lunahalfmoon.com.
2. What stays on your phone
Everything you enter in Luna is saved in the app’s private storage on your device:
- Period days and flow, symptoms and how strong they were, moods and notes
- Fertility signs if you track them: ovulation (LH) tests, cervical mucus and waking temperature
- Sex and pregnancy tests if you track them
- Your health profile: conditions such as PCOS or endometriosis, birth control, breastfeeding and your goal
- Your first name (optional), settings, reminders and your Ask Luna conversation
Luna works out your predictions on your phone. This information is not uploaded to us or anyone else, and we have no way to see it. It is protected by your phone’s own security, and you can add Luna’s App lock (Face ID, fingerprint or passcode) in Settings.
If you delete Luna or tap Delete everything in Settings, this data is removed from your phone. We can’t recover it for you, so consider making a backup first (see section 5).
3. Ask Luna (optional AI assistant)
Ask Luna answers questions about periods and cycles. It is off until you agree to it, and you can turn it off at any time in Settings → Privacy → Ask Luna (AI).
When you send a question, Luna sends the following to our server and on to the AI service:
| Sent | Never sent |
|---|---|
|
Your question and the recent messages in the conversation (up to 12) A short cycle summary: cycle day and phase, average cycle length, days until your next period, today’s fertility estimate and how ovulation was detected, conditions in your health profile, your goal, and symptoms from the past 7 days |
Your name Your calendar and day-by-day logs Your notes Your sex and pregnancy-test entries |
Who processes it. Our server runs on Supabase in the United Kingdom (London). It passes your question to Anthropic, the company that makes the Claude AI models, which writes the answer. Our server does not save your questions or the answers. Anthropic’s published policy for its API is that it does not train its models on this data by default, and deletes it from its systems within 30 days. It may keep data longer when needed to enforce its usage policies or comply with the law. Anthropic processes data in the United States.
Answers from Ask Luna are general information, not medical advice, and can be wrong.
4. Protecting Ask Luna from abuse
To stop anyone misusing Ask Luna, our server counts how many questions are asked each day. For this it stores:
- a random ID created when Luna is installed (it is not linked to your name, your phone number or your Apple or Google account)
- a scrambled (hashed) version of the internet address the question came from
- the number of questions asked that day
These counters contain no health information and are deleted automatically after 2 days. Like most online services, our hosting provider also keeps short-lived technical logs, such as the time of a request, for security and reliability.
Reporting an answer
If you tap Report under an Ask Luna answer, Luna sends us that answer, the question you asked just before it and the reason you chose, so we can review it and improve Ask Luna. A report never includes your name or your cycle data. To stop one phone flooding us with reports, it is stored with a one-way scrambled version of the install ID. Reports are deleted after 90 days.
5. Things you choose to share
Luna can create files on your phone. Each one stays on your phone until you choose where to send or save it with your phone’s share menu:
- Report for your doctor (PDF): your periods, cycle lengths and symptoms, plus your name, health background and notes only if you switch them on. Sex and pregnancy-test entries are never included.
- Backup file: a copy of everything in Luna, so you can restore it on a new phone. It contains your health information, so keep it somewhere private.
- Spreadsheet (CSV): your daily logs, for your own records.
Once you send or save a file somewhere (for example email, iCloud Drive or Google Drive), that service’s own privacy terms apply to it.
6. Reminders and App lock
Reminders are scheduled on your phone; we don’t run a notification server. With Discreet notifications on (the default), reminders show “Luna reminder” and no period details. App lock uses your phone’s Face ID, fingerprint or passcode; Luna never receives your biometric data.
7. What we don’t do
- We don’t sell, rent or trade your data, and we don’t share it with advertisers, data brokers, employers or insurers.
- We don’t show ads and don’t use analytics, advertising IDs or tracking tools.
- We don’t require an account, email address or phone number.
- We don’t use your data to train AI models.
8. Requests from authorities
Because your cycle logs are stored only on your phone, we don’t hold them and can’t hand them over to anyone, including in response to a legal request. The only things our server holds are the short-lived counters and any answer reports described in section 4.
9. Legal bases (EU, UK and similar laws)
- Ask Luna: your explicit consent, which you give in the app before first use and can withdraw at any time in Settings. Withdrawing doesn’t affect questions already answered.
- Abuse-protection counters and technical logs: our legitimate interest in keeping the service secure and affordable.
- Answer reports: our legitimate interest in keeping Ask Luna safe and accurate.
Ask Luna involves sending data to the United States. Where the law requires it, these transfers rely on safeguards such as standard contractual clauses provided by our service providers.
10. Your rights and choices
Depending on where you live, you may have rights to access, correct, delete, restrict or object to the use of your personal data, to data portability, and to withdraw consent. For data on your phone, you can do all of this yourself in Luna: view and edit your logs, export a backup or spreadsheet, turn off Ask Luna, or delete everything. For anything else, contact us at support@lunahalfmoon.com. You can also complain to your local data protection authority.
11. Children
Luna is for people aged 13 and over. If you are under the age where your country’s law lets you agree to this on your own (for example, under 16 in some EU countries), please ask a parent or guardian before turning on Ask Luna. We don’t knowingly collect personal data from children under 13.
12. Security
Your logs never leave your phone unless you send them. Ask Luna uses an encrypted connection (HTTPS), and the AI service key is kept on our server, never inside the app. No system is perfectly secure, so we keep what we hold to the minimum described above.
13. Changes to this policy
If we change how Luna uses data, we will update this page and the date at the top. If a change affects what leaves your phone, we will ask for your consent again in the app first.
14. Contact
Questions or requests about privacy: support@lunahalfmoon.com.