Support

We're here to help. Reach us at support@nof1.app or browse the FAQs below.

Quick contact: Email us at support@nof1.app and we'll respond within 1–2 business days. For billing or subscription issues, use Settings → Manage Subscription inside the app to contact Apple directly.

Frequently Asked Questions

Getting Started

What is an N-of-1 trial?

An N-of-1 trial is a personal experiment where you are both the subject and the scientist. You measure a health metric (like sleep duration or resting heart rate) before and after making a lifestyle change — for example, cutting out caffeine or adding a daily walk. N of 1 automates all the data collection and statistics so you can see whether the change actually made a measurable difference for you.

Which iPhone and iOS version do I need?

N of 1 requires iOS 16.0 or later and is compatible with iPhone 12 and newer. An Apple Watch is recommended for the best data quality but is not required — the app works with any iPhone health data including steps, sleep (from third-party apps), and more.

Does the app work without an Apple Watch?

Yes. N of 1 reads data that is already stored in your Apple Health app, regardless of the source. If you wear an Apple Watch, sleep analysis and heart rate data will be richer, but the app works fine with iPhone-only data like step count and active energy.

HealthKit & Data

Why does N of 1 need access to my health data?

N of 1 reads your health data from Apple Health to calculate the statistics for your experiments. It is read-only — the app never writes anything to Apple Health, and your health data never leaves your device. All processing happens locally in the app.

How do I grant or revoke HealthKit permissions?

You can manage permissions at any time in iOS Settings → Privacy & Security → Health → N of 1. You can turn individual metric types on or off. Revoking access for a metric will prevent the app from tracking it in future experiments, but will not affect existing results already saved.

Why does a metric show "Insufficient Data"?

This usually means one of the following:

Try choosing a retroactive baseline using your most recent 14 days of data, which often has better coverage than older periods.

Is my health data shared with anyone?

No. Your health data is processed entirely on your device and is never sent to any server. The only external service we use is RevenueCat for subscription management — it receives anonymised purchase receipts, not health data. See our Privacy Policy for full details.

Experiments

How long should an experiment run?

We recommend a minimum of 14 days for each phase (baseline and trial) to give the statistics enough data to be meaningful. Longer is generally better. Short-lived changes (like a single night of bad sleep) can be recorded as confounding factors without ending the experiment early.

Can I run multiple experiments at the same time?

Free accounts support one active experiment at a time. N of 1 Premium allows unlimited concurrent experiments. If you want to track several interventions simultaneously, consider upgrading or running them sequentially.

What is a retroactive baseline?

Instead of waiting 14 days to collect baseline data before starting an intervention, you can use your past 14 days of Apple Health data as your baseline and begin the trial immediately. This works well if your habits haven't changed recently and you already have good historical data in Apple Health.

How do I record a confounding factor?

During an active experiment, tap the + Note button on the Home screen. You can log things like a night of poor sleep, illness, travel, or any other factor that might have affected your metrics on a given day. These notes appear on your results charts so you can interpret anomalies in context.

Subscriptions & Billing

What's included in the free tier?

The free tier lets you run one experiment at a time with all core features: retroactive baselines, statistical results, time-series charts, and confounding factor notes. Premium unlocks unlimited concurrent experiments and AI-powered result summaries.

How do I manage or cancel my subscription?

You can manage your subscription directly through Apple:

Cancellation takes effect at the end of your current billing period. We cannot process refunds directly — all refunds must be requested through Apple.

How do I restore my subscription on a new device?

Open N of 1, go to Settings → Restore Purchases, and sign in with the same Apple ID you used to purchase the subscription. Your Premium access will be restored automatically.

Privacy & Security

Does N of 1 have a backend server?

No. There are no N of 1 servers that receive or store your data. The app is entirely offline-first. Your experiments, results, and health data are stored in a local SQLite database on your device, encrypted at rest by iOS.

What happens to my data if I delete the app?

All app data (experiments, notes, settings) stored in N of 1's local database will be permanently deleted when you remove the app. Your underlying Apple Health data is unaffected — it remains in the Health app and is not controlled by N of 1.

Contact Us

If you didn't find the answer you were looking for, please reach out:

We aim to respond to all support emails within 1–2 business days.