How Kaizin handles your data

Last updated 27 September 2026

In short, we collect the health information you choose to give Kaizin, we use it only to run Kaizin for you, it is stored in London, and we never sell it or use it for advertising. You can see it, take a copy, or delete it whenever you like.

Who we are

Kaizin is run by Olympus Premium Health Limited, a company registered in England and Wales (company number 13621708), registered office 82A James Carter Road, Mildenhall, Bury St Edmunds, Suffolk, IP28 7DE. We are the controller of your personal data, and we are registered with the Information Commissioner's Office (registration number C1928947).

For anything about your data, email hello@kaizin.health.

What we collect

Data	Where it comes from	Why we use it
Your email address	You, when you sign in	To create your account and send sign-in codes
Date of birth, sex, and which wearable you use	You, on your profile	To read your results against the right ranges and label your wearable data correctly
Blood test PDFs and the results in them	You, when you upload a panel	To show your results and for our doctor's review
Our doctor's review and recommended change	The doctor who reviews your panel	To show you what to focus on
Resting heart rate, HRV, sleep (including stages and times), steps, and heart rate during the day	Apple Health, if you allow it	To show your readings against your own normal and estimate daily strain
Overnight HRV, lowest heart rate, sleep (including stages and times), and steps	Oura, if you connect your Oura account	The same as Apple Health
Weight, blood pressure and other readings you type in	You	To track them over time
Day tags (for example alcohol or a late meal)	You	To show how your readings change after those days
Questions you ask about your results	You	To answer them

Reminder times and your Face ID or passcode setting stay on your iPhone and are never sent to us. Face ID itself is handled by iOS, and Kaizin never sees it.

Our legal basis

Health information is special category data under UK GDPR. We process it with your explicit consent (Article 9(2)(a)), which you give when you upload a panel, allow Apple Health access, or connect Oura. We process your account details to provide the service you signed up for (Article 6(1)(b)). You can withdraw consent at any time by disconnecting a source or deleting your account. Withdrawing consent doesn't affect what we did before.

Apple Health and Oura

Kaizin only reads from Apple Health. It never writes to it. You choose which data types to share in iOS, and you can change that in the Health app at any time.

When you connect Oura, you sign in on Oura's own page and approve access to your daily sleep and activity data. We keep Oura's access keys encrypted on our servers, and they never reach your phone. If you disconnect Oura, we revoke access straight away and you can choose to delete the Oura readings we hold.

Data from Apple Health and Oura is used only to run Kaizin for you. We never use it for advertising, never sell it, and never share it with data brokers.

Who we share it with

We don't sell your data. We only share it with the service providers we need to run Kaizin, under contracts that require them to protect it and use it only on our instructions:

Supabase hosts our database, file storage and sign-in. Your data is stored in London (AWS eu-west-2).
Google (Gemini API) reads the text of an uploaded lab PDF to pick out each result, and drafts answers to questions you ask about your results. We send only what is needed for that task. Google may process this outside the UK. Where it does, the transfer is covered by the UK International Data Transfer Addendum or an equivalent safeguard.
Our reviewing doctor sees your panel and profile to review it. They are bound by medical confidentiality.
Oura, only if you connect it. We receive data from Oura and send nothing back beyond what is needed to sign in and sync.

We may also disclose data if the law requires it, or to protect someone's life in an emergency.

How long we keep it

We keep your data while your account is open. If you delete your account, we delete your results, readings, tags and profile within 30 days, and remove them from backups within a further 30 days. If you disconnect Oura and ask us to, we delete your Oura readings straight away.

Your rights

You can ask us to:

give you a copy of your data
correct anything that is wrong
delete your data
stop or limit how we use it
send your data to you or another service in a common format

Email hello@kaizin.health from the address on your account. We reply within one month. If you are unhappy with how we handle your data, you can complain to the Information Commissioner's Office at ico.org.uk.

Security

Data is encrypted in transit and at rest. Every record in our database is locked to your account, so no other user can read it. Oura access keys are encrypted again before they are stored. You can lock Kaizin with Face ID or your passcode.

Children

Kaizin is for adults aged 18 and over. We don't knowingly collect data from anyone younger.

This website

kaizin.health sets no cookies and runs no analytics or advertising trackers. Our hosting provider (Vercel) keeps standard server logs, such as IP addresses, for security, for a short time.

Changes

If we change this policy in a way that affects you, we will tell you in the app before the change takes effect. The date at the top shows the latest version.