Privacy Policy
Gutli asks you to record how your body is doing. That is sensitive information, and this page sets out exactly what happens to it.
- Effective
- 22 August 2026
- Last updated
- 27 August 2026
1. Who we are
Gutli is operated by Darkmode Ltd (“we”, “us”), a company registered in England and Wales under company number 17377649, with its registered office at 58 Bramah House, Gatliff Road, London SW1W 8DT, United Kingdom.
Darkmode Ltd is the data controller for the personal data described here. That means we decide what is collected and why, and we are accountable for it. This policy covers the Gutli app and this website.
You can reach us at hello@gutli.co about anything on this page.
2. What Gutli does
Gutli helps you understand your gut health through structured experiments. You sign in with Apple, then record what is actually happening: meals — typed in, scanned from a barcode, read from a food label, or photographed — alongside symptoms, bowel movements, journal entries, and lifestyle factors such as sleep, stress, caffeine and alcohol.
You also tell Gutli what you already suspect about your own gut. Gutli turns that belief into an experiment: take one suspect food out, put it back, and see whether your symptoms follow. At the end of the experiment, you get a result.
Everything in this policy follows from that. Gutli holds what you log because your history is the thing an experiment is run on.
3. What we collect
There are two kinds of data here: the details attached to your account, and the things you choose to record.
| Category | What it includes |
|---|---|
| Account data | Your name, if you share it through Sign in with Apple; your email address, or Apple’s private relay address if you use Hide My Email; and, if you enter them, your date of birth, height, weight and gender. |
| Your settings | Your calorie goal, the foods you have flagged as triggers, your app preferences and the choices you made during onboarding. |
| What you record | Meals and their ingredients, meal photos and food labels you upload or scan, symptoms and their severity, bowel movements and stool information, journal entries, and context you report such as sleep, stress, alcohol, caffeine, medication changes, illness and travel. |
| Experiment data | The beliefs you are testing, your safety screening answers, your progress through each phase, the results Gutli produces, and your completed experiment history. |
| Purchase data | A record of the experiments you have bought, and how many you have left to run. We never receive or store your card details. |
| Support correspondence | If you email us, your message, our reply, and the address you sent it from. |
We do not read Apple Health, and we do not access your location, your contacts, or your photo library beyond the individual photos you choose to add to a meal.
4. Your health data
Your symptoms, stool records, medication changes, illness and how you felt on a given day are information about your health. Under the UK GDPR and EU GDPR that is special category data, and it gets stronger protection than ordinary personal data.
We process it only with your explicit consent, which you give when you choose to record it. You can withdraw that consent at any time by deleting the entries, or by deleting your account. Withdrawing consent does not undo processing that already happened, and it ends your ability to run experiments, because there is nothing left to run them on.
5. Why we use it
| What we do | Why we are allowed to |
|---|---|
| Create your account, sign you in, and keep your entries available across your devices and reinstalls | To provide the service you signed up for (our contract) |
| Store what you log and run the experiments that turn it into a result | Our contract with you, and your explicit consent for the health-related parts |
| Sell experiments and keep a record of what you have paid for | Our contract with you |
| Keep the app working, fix faults, and keep it secure | Our legitimate interest in running a reliable, secure product |
| Answer your support emails | Our contract with you, and our legitimate interests |
| Keep the records the law requires, such as purchase records | Our legal obligations |
We never rely on legitimate interests for your health data. That always rests on your consent.
6. Meal analysis and results
When you photograph a meal, scan a food label, or describe what you ate, Gutli sends that food content to OpenAI so it can identify the ingredients and produce a nutritional analysis. Only food-related content is sent: the meal photo or label image, the ingredient text, and your description of the meal.
OpenAI does not receive your symptom logs, journal entries, experiment history, gut scores, safety screening answers or private notes. If that ever changes in a future version of the app, we will update this policy and tell you before the change takes effect.
Your experiment result is calculated automatically from the entries you logged — no one reviews it by hand. It is information for you to interpret and to discuss with a healthcare professional. It is not a diagnosis, and it does not decide anything about you.
7. Who else processes it
We use a small number of service providers. They process personal data on our instructions, under contract, and are not permitted to use it for their own purposes.
| Provider | What they do | What they receive |
|---|---|---|
| Apple | Sign in with Apple, and App Store in-app purchases. Apple handles authentication and payment. | Your Apple account identifier, the name and email address you choose to share, and your purchase records. Your card details go to Apple, never to us. |
| Supabase | Stores user accounts and application data | Your account data, your settings, and everything you record in the app |
| OpenAI | Analyses meal photos, food label photos, ingredient text and meal descriptions | That food content only. No symptoms, journal entries, experiment history, gut scores, safety screening answers or notes. |
| Open Food Facts | Looks up food products you scan | The barcode number. Nothing about you. |
| Superwall | Presents the screen on which an experiment is bought | A device or user identifier, and how you interacted with the purchase screen. No health data. |
We may also disclose personal data where the law requires it, for example in response to a valid court order, or where it is necessary to establish or defend legal claims. If Darkmode Ltd is ever involved in a merger, acquisition or sale of assets, your data may transfer to the acquiring party, and we will tell you before that happens.
8. What we never do
- We do not sell your personal information.
- We do not use your health data for advertising.
- We do not build advertising profiles.
- We do not share your health data with advertisers, data brokers, insurers or employers.
9. Emails and notifications
We do not send marketing emails. Anything you receive from us is about your account, or a reply to something you asked.
Where you turn them on, the app can send experiment reminders and essential service notifications. You can switch these off at any time in your device settings or in the app.
10. This website and cookies
This website uses only essential cookies and the standard functionality needed to serve these pages. There is no advertising, no tracking and no visitor profiling.
Like any web server, ours processes ordinary request information — your IP address, the page requested, the time, and your browser’s user agent — to deliver pages securely and reliably. We do not combine it with your app account.
11. International transfers
Our providers operate internationally, so your personal data may be stored or processed outside the country you live in, including in the United States.
Where personal data leaves the UK or the European Economic Area, it is protected by appropriate safeguards: an adequacy decision where one applies, and otherwise the UK International Data Transfer Agreement or the European Commission’s Standard Contractual Clauses. You can ask us which applies to a particular provider.
12. Keeping and deleting your data
We keep what you log for as long as your account exists. Your history is the point of the product — an experiment you ran last year is what this year’s result gets compared against.
You can delete your account from inside the app. Deleting your account removes the account data Gutli stores: your profile and settings, your meals, symptoms, journal entries, beliefs and experiment history. Secure backup copies may remain for a short period afterwards before they are automatically overwritten in the normal backup rotation.
Deletion is permanent. Completed experiments and the results they produced cannot be recovered afterwards, by you or by us. If you want to keep them, ask us for a copy of your data before you delete. Note that deleting the app from your device is not the same as deleting your account — uninstalling removes the app, and your account remains until you delete it.
If you cannot reach the in-app option for any reason, email hello@gutli.co from the address on your account and we will action it.
Two things outlast your account: purchase records, which we keep for as long as tax and accounting law requires, and support emails, which we keep for as long as we need them to handle your request and anything that follows from it.
13. Your rights
If you are in the UK or the European Economic Area you have the following rights over your personal data. We honour these requests for everyone, wherever they live.
- Access. Get a copy of the personal data we hold about you.
- Correction. Have inaccurate data fixed. Most of it you can edit directly in the app.
- Erasure. Have your data deleted — see Keeping and deleting your data.
- Portability. Receive your data in a structured, machine-readable format.
- Restriction. Ask us to limit how we use your data while a dispute about it is resolved.
- Objection. Object to processing we carry out on the basis of our legitimate interests.
- Withdraw consent. Withdraw your consent to health data processing at any time.
To exercise any of these, email hello@gutli.co. We will respond within one month, free of charge, and we will not ask you to justify the request. We may need to check that the request came from you.
If you are unhappy with how we have handled your data, you can complain to your local data protection authority — in the UK, the Information Commissioner’s Office. We would rather you came to us first so we can put it right.
14. Security
Your data travels over encrypted connections, sign-in is handled by Apple and Supabase rather than by passwords we hold, and access to production data is limited to the people who need it to operate the service. We apply industry-standard technical and organisational measures to protect it.
No system is perfectly secure, and we will not claim otherwise. If a breach occurs that is likely to result in a risk to your rights and freedoms, we will notify the relevant supervisory authority within 72 hours and tell you without undue delay where the law requires it.
15. Age requirement
Gutli is intended for people aged 16 and over. We do not knowingly collect personal data from anyone younger. If you believe a child has given us their data, email hello@gutli.co and we will delete it.
16. Changes to this policy
If we change this policy we will update the date at the top of this page. Where a change materially affects how we handle your data, we will tell you in the app or by email before it takes effect, and where the change relies on your consent we will ask for it again.
17. Contact us
For any question about this policy, or to exercise your rights, contact us at hello@gutli.co, or write to us at:
Darkmode Ltd
58 Bramah House
Gatliff Road
London
SW1W 8DT
United Kingdom
See also our Terms of Service and our Support page.