Luteum is a period tracker that keeps your cycle to itself. Everything you log stays on your phone.
On your device, and nowhere else. There is no Luteum account and no Luteum server. If you use iPhone backup, your data is included in that backup — encrypted under Apple's protection, never ours.
Settings → Your data → Export. You can take everything as a spreadsheet (CSV), a full data file (JSON), or a one-page PDF summary to give to a clinician.
Settings → Your data → Delete all data. This removes every day you've logged from your phone, along with any pending reminders. Because we hold no copy, it cannot be undone.
Because your cycle length isn't a setting — it's the average of your own recent cycles, recalculated every time you log. Luteum asks for a rough figure when you first open it, then replaces it with your real pattern.
Because it's an estimate. Early on the range is wide and honest about it; as you log more cycles it narrows to your own pattern. If your cycles are irregular, Luteum says so rather than inventing a confident date.
Luteum has no account and no server, so nobody can reset a PIN for you. If you switched on passcode recovery in Settings → App Lock, use "Forgot PIN?" on the lock screen. Otherwise deleting the app removes the lock and the logged data together.
It's a one-time tip that keeps the app independent — no ads, no trackers, no data deals. It unlocks some cosmetic extras as a thank-you. Nothing about your health is ever behind a paywall.