The timer, and the plans and stages to 36 hours, are free, for good.

Not yet. Nesteia is in testing on iPhone and is not on the App Store yet, and there is no release date to give. You can join the public beta through Apple's TestFlight app; purchases in the beta are free test purchases. The prices on this page are the ones it will launch with; there is nothing to buy today.

No. It is a timer with an evidence register. Each stage describes what studies measured in healthy adults, with the paper cited and a confidence label. If you have a condition, take medication, are pregnant or breastfeeding, or have any history of disordered eating, talk to your GP before fasting.

No account. The app collects nothing: it has no analytics and no third-party SDKs, and there is no server of ours for it to talk to, so we never see a fast. Your history stays on your phone unless you turn on iCloud sync, which keeps a copy in your own private iCloud database. The privacy policy has the detail.

Published safety data for unsupervised fasting stop at about 72 hours, so every unsupervised plan in Nesteia does too. The 96 and 120‑hour plans exist for people fasting under a clinician: before each such fast you confirm that a clinician is supervising it, that your electrolytes are being monitored and that a graded refeed of at least three days is planned, and the confirmation is recorded on the fast.

Fasts longer than 120 hours have been studied only in supervised clinical settings, so nothing in the app passes that point: the timer, plan picker, custom lengths, start-time edits, CSV import, deep links, the Live Activity and widgets all stop at 120 hours, and a running fast ends itself there.

Yes. The plan picker has a Custom row with a stepper from 12 to 72 hours. It is gated like the built-in plans: screening once for anything over 16 hours, the acknowledgement for 48 hours or more, and Pro beyond 36 hours. 96 and 120 hours exist only as the supervised built-in plans.

Undo. For two minutes after any end, an Undo button restores the fast exactly as it was, ring and stage included. After that, History offers Resume on the most recent fast for ten minutes after it ended. There is no pause button: a fast is either running or over.

No. The outcomes evidence does not support them, so the app describes physiology only. Across 99 trials, intermittent-fasting forms perform about the same as continuous daily restriction, and there is no human evidence that fasting extends life.

Rigid counters push some people to fast longer or more often than planned, and the eating-disorder research points at exactly that rigidity. Nesteia shows a twelve-day rhythm strip with grace days and rest weeks, and the Rhythm badges count kept daily windows inside fixed blocks of seven or twelve days, never a run of days.

"Measured in humans · high" means direct measurement in healthy adults across several studies. "Moderate" means fewer or smaller studies, or wider variation between people. "Animal or indirect evidence · low" is used only for explainer cards, which is why autophagy is never a stage.

Only if you turn it on. iCloud sync is a Pro setting, off by default. When it is on, your fasts, weight entries, refeed meals, rest weeks and badges are stored in your own private iCloud database under your Apple Account, and we never see them; your screening answers and settings stay on each phone. With it off, your history lives on one iPhone; a JSON archive, exported from Settings and imported on the other phone, moves everything, and CSV moves the fasts alone. Sync needs iCloud Drive turned on.

Once Nesteia is on the App Store: iPhone Settings, your name, Subscriptions, then cancel Nesteia Pro. Apple will manage the subscription, the 14‑day trial on the annual plan (if your Apple Account is eligible for the introductory offer) and any refund. Cancelling during the trial means you are not charged. Restore purchases will be in the app's Settings, with Manage subscription beside it once Pro is active.

Through Apple, once Nesteia is on the App Store. Apple will take the payment and handle any refund, which you ask for at reportaproblem.apple.com; we cannot process refunds ourselves. As a consumer in the UK you have a right to cancel a digital purchase within 14 days, unless you asked for the content to be supplied immediately and acknowledged that you would give up that right. The terms set this out in sections 5 and 6.

No. Family Sharing is off for all three purchases, monthly, annual and lifetime, so Pro will belong to the Apple Account that buys it.

One payment of £99.99, with no renewal and nothing further to pay. As the terms put it, it is a one-off payment for the current version of Pro, for as long as the app is available on the App Store.

Not yet. iPhone first; Android is planned for a later release.