Privacy
The short version
We keep as little about you as the work allows, and we say what we keep. We do not sell anything about you, we run no advertising trackers, and there is no cookie banner, because we place nothing that needs your consent.
One exception, and it belongs at the top rather than buried somewhere below. Make an account and record your own measurements there, and we keep them for you. We do that only because you put them there yourself, you can throw them away one at a time or all at once with a button on that page, and nothing else happens with them.
To read a guide you leave nothing behind. No account, no email address.
Where a section below says "basis", it means the legal ground we rely on to process something at all. Health information carries a stricter one than an address does, and we have written which is which rather than covering everything with a single sentence.
Who is responsible
Liam "Kratos" Krassenburg, trading as Kratos Natural, Clausstraat 6, 2661 BZ Bergschenhoek, Netherlands. KVK 92192475. Reach us at info@kratosnatural.com.
We are the controller within the meaning of the General Data Protection Regulation. We answer questions about your data ourselves: there is no form and no ticket queue.
What we process, and why
Orders. When you buy something we process your name, email address, delivery address and the details of the order. We need it to fulfil the contract, and tax law requires us to keep the records. Basis: performance of a contract, and a legal obligation.
Payment. Your card details go straight to Stripe and never reach us. We see whether the payment succeeded, the amount, the country, and the email address you gave at checkout. We never see your full card number.
Signing in. When you sign in we set a cookie holding your email address, signed so it cannot be tampered with. There is nothing else in it and we store nothing alongside it. It is strictly necessary to keep you signed in, which is the one kind of cookie that needs no consent.
Coaching. If you buy coaching we process your name, email address and what you bought, to carry out the agreement and because we are legally required to keep the records. If you ask us to start immediately, the moment you asked is recorded with your payment, because it determines what withdrawing costs.
The intake questionnaire. Before an intake conversation we send you a questionnaire hosted by Tally. It asks about your health, and your answers sit on Tally's servers inside the European Union before they reach us. Basis: your explicit consent, given by filling it in. You may leave any question blank; we will ask it in the conversation instead.
Booking a conversation. Appointments run through Cal.com. You give them your name, your email address and a time.
The coaching itself. What you say in a conversation stays between us. Part of it concerns your health, which the law calls a special category of personal data. We process it only because you explicitly agree to by starting. We do not share it, and we will not use you as an example, not even anonymously, without asking first and accepting no.
The newsletter. If you subscribe we keep your email address with Resend for as long as you stay subscribed. Basis: your consent. The unsubscribe link is at the foot of every email and it works immediately.
Getting in touch. If you email us we keep that email for as long as it takes to deal with your question, and so that we can look back if you return to it later.
Your account. If you create an account we keep your email address and, if you set one, your password. We never keep a password as you typed it: a one-way calculation (scrypt) runs over it and the original cannot be recovered from the result, by us or by anybody else.
Measurements you record. When you record something in Kratos Hub, such as your biological age, your grip strength, a blood value or how long you slept, we keep it with its date. That is information about your health, a special category under the law, and we process it only because you enter it there yourself. Basis: your explicit consent, given by filling the value in.
What does not happen to it: we do not sell it, we share it with nobody, it goes to no analytics package, and we do not read it to recommend you anything beyond the page where you see it yourself. The suggestions on that page are assembled in your own browser out of what is already there.
A connected ring or watch. If you connect your Oura account to the hub, the permission you give covers seven things:
Your sleep.
Your daily summaries: activity, readiness, stress and the cardiovascular estimate.
Your heart rate and heart rate variability.
Your workouts and sessions.
Your blood oxygen.
The tags you set in Oura yourself.
Your basic details, such as age, sex, height and weight.
Oura's own consent screen shows you exactly what we may fetch before you agree, and we can fetch nothing outside it.
What we actually read today is narrower than what you allow: your sleep, your resting heart rate, your heart rate variability, your steps and your VO2 max. The permission is wider because the hub is being built out and we would rather ask you once than send you back to a consent screen every time a screen is added. Anything new we begin reading is named here first.
We are told by Oura when something of yours has changed, and we then fetch it ourselves over an authenticated connection; once a day we also check for anything that notice missed. Nothing a ring writes ever replaces a value you entered by hand.
A connected training app. If you connect Strava, we read your activities: what you did, how long it lasted, how far it went, roughly how many calories it cost, and your average heart rate. We ask for read-only permission, so nothing we do can change, add to or delete anything on your Strava. Your activities are fetched when you connect and once a day after that.
Basis: your explicit consent, given by making the connection, the same as for a ring.
You can disconnect whenever you like. You then choose: break the connection only, or also delete every session it wrote. Sessions you entered yourself stay in both cases.
A connected strap. If you connect Whoop, we read your nights and your sessions. From the night: how long you slept, how much of that you were awake, your resting heart rate and your heart rate variability. From a session: what it was, how long it lasted, how far it went, roughly what it cost and your average heart rate.
We ask for read-only permission, so nothing we do can change anything on your Whoop, and we do not ask for your body measurements.
Basis: your explicit consent, given by making the connection, the same as for a ring.
Where a ring and a training app both record the same session, we keep one of them, the first one recorded, so that one hour of training is not counted as two. The same holds for a night that two devices both measured: the first one recorded stands and the second is ignored, rather than the two taking turns rewriting the same night.
Basis: your explicit consent, given by making the connection. That is a different consent from the one you give by typing a value in, and we record which of the two every stored value rests on.
We do not ask Oura for your email address, because we already have it from your account, and we do not ask for your ring settings, because we do nothing with them.
You can disconnect whenever you like and the fetching stops at once. You then choose: break the connection only, or also delete everything the ring wrote. What you entered yourself stays in both cases, unless you ask for that separately.
Deleting. You do it yourself, immediately. In Kratos Hub you throw away one value or everything at once, and with everything the account goes too. You do not have to ask us.
If you fill values in without being signed in they stay in your own browser and never reach us at all, and they are not moved onto an account later. Separately from that: a value you saved while signed in that we could not store, because the connection failed, waits in your browser and is sent again the next time it can be. That one you already asked us to keep.
Photographs you take. The hub can read a photograph for you: a blood test result, a product label, a plate of food, a page of your own handwriting. The picture is sent to Anthropic, which runs the model that reads it, and it is read there and dropped. We store no photograph, not the picture and not a copy of it, and nothing is kept on Anthropic's side to train anything. What stays afterwards is what you confirmed: the values you ticked, in your own account, exactly as if you had typed them.
Basis: your explicit consent, given by choosing the photograph. Nothing is sent until you pick a file, and every reader offers the typing route instead.
The reading is never the last word. What comes back is checked against our own tables and put in front of you to confirm or correct before anything is stored, and where a value was estimated rather than read it stays marked as an estimate until you overwrite it.
Speaking instead of typing. Where you can talk to the hub rather than type, the listening is done by your own browser. On Chrome and on Safari that means the sound of your voice goes to Google or to Apple, whose speech recognition it is, under their terms rather than ours. We receive only the text your browser produces, and it is treated from there like anything you typed. The microphone stops the moment you leave the page.
The assistant in the hub. You can ask the hub a question in your own words. What is sent to the model is your question and nothing else: not your values, not your account, not your name. The model answers by naming which of our own screens or figures answers it, and the answer itself is then assembled in your own browser out of what is already there. That is deliberate. It means a model is never given anybody's health data, and a service outage costs you an answer rather than your privacy.
Questions you ask on the site. The ask box on the questions page is open to anybody, with no account. Your question goes to Anthropic to be matched against what we have published, and comes back with the piece that answers it or with an honest "we have not looked at that yet".
We keep your question only if you tick the box that says so, and the box is off until you tick it. What is kept is the sentence and the language and the date, and nothing else: no address, no cookie, nothing that says it was you. We keep it for one reason, which is that a question one person asks is usually a question many people have, and the ones our library could not answer are the list of what we write next.
Asking whether guidance would help you. The form on the guidance page asks what is going on, and what you write there is often about your health. It is emailed to us and nowhere else, and nothing about it is stored: no database row, no list, no record beyond the message itself. Basis: your explicit consent, given by sending it. We answer as people, and if the honest answer is that you do not need us, that is the answer you get.
The longevity roadmap. If you ask for the roadmap we keep your name, your email address and your answers to the seven questions on the form. That is what it takes to work out which roadmap answers your situation and to send it to you. We do not ask for a postal address, because nothing is ever posted to you. Basis: your explicit consent, given by sending the form. What you agreed to is stored with the record, in the words that were on the screen, so it can be shown rather than asserted.
Whether we may call you. The same form carries one box, empty until you tick it, asking whether we may reach you by phone, text or WhatsApp about the guidance. Your number is only asked for after you tick it, and it is only kept if you did. Leave the box alone and the roadmap still arrives: this is a separate permission, not the price of the file. Basis: your consent, and one reply takes it back.
We do not sell it and we do not pass it on. Ask us to stop contacting you and we stop, and ask us to delete it and it is gone; one email does either.
Downloads. We record nothing when you download a guide or an e-book. There is no counter, no form and no account. We do not know who downloaded what.
What we do not do
We do not sell your data and we do not rent it out.
We use no advertising trackers, no Facebook pixel and no Google Analytics.
We make no automated decisions with legal effects and we do no profiling.
Statistics
We use Vercel Analytics and Speed Insights, which count page views and load times without cookies and without following you between websites. We cannot see individual people in it.
Who processes your data on our behalf
Vercel, hosting the website, inside the European Union.
Stripe, payments and the record of your order.
Resend, sending sign-in emails, order confirmations and the newsletter.
PostNL, delivering your parcel. They get your name and address, nothing else.
Cal.com, scheduling conversations.
Tally, the intake questionnaire. Based in Belgium, so the health information in it stays inside the European Union.
Anthropic, the model that reads a photograph and that matches a question to what we have published. They get what you send at that moment and keep nothing afterwards, and they are never shown a value out of your account.
Neon, the database behind your account and your measurements. We choose a region inside the European Union when it is created, so your data does not leave the Union. The connection is encrypted and so is the storage.
A processing agreement is in place with each of them, and each processes only what its part of the work needs. Some are established in the United States. Those transfers rest on the European Commission's standard contractual clauses or on a valid adequacy decision.
Oura, Strava and Whoop are not processors for us. Each of them is your own account with them, and we fetch from it only what you have allowed. How they handle your data is governed by their own policies.
How long we keep things
Invoices and order details: seven years, because the tax authority requires it.
Coaching notes and anything about your health: the length of the protocol and two years after it, so we can pick up where we left off if you come back. Ask us sooner and we delete them.
Your account and the measurements in it, whether you entered them yourself or they arrive from a connected ring: until you throw them away. We do not tidy them up by ourselves and we do not keep them longer than you want. There is no retention period on them, because the series is yours and it only says something once it is long enough. Throw everything away and it is gone, including from the backups as soon as those expire.
Newsletter subscription: until you unsubscribe.
Email correspondence: as long as handling it needs, then cleared out.
A photograph you had read: not at all. It exists for the seconds the reading takes.
A question you let us keep: until it has been answered on the site, and then it is what the piece was written for rather than a record of anybody.
The sign-in cookie: until it expires or you sign out.
Your rights
You have the right to see what we hold about you, to have it corrected, to have it deleted, to have the processing restricted, to take your data with you, and to object to the processing. Where you have given consent you may withdraw it at any moment, and that does not touch what was processed before you did. For your account and your measurements you do not have to ask at all: the buttons are on the page.
Write to info@kratosnatural.com and we answer within a month, usually the same week. You do not have to give a reason and it costs nothing.
If you think we are handling your data badly you may complain to the Dutch Data Protection Authority, the Autoriteit Persoonsgegevens. Tell us first if you can, so we can put it right.
Security
The site runs entirely over HTTPS. A password is optional, and it is never kept as you typed it: a one-way calculation (scrypt) runs over it and the original cannot be recovered from the result. Payment details never touch our servers, and access to the database is limited to what the site itself needs.
We will not pretend to be a bank. No measure is perfect and we do not promise ours is. If something goes wrong that affects you, you will hear it from us.
Children
The site is not aimed at people under sixteen, and we knowingly process nothing about them. If you think we have anyway, tell us and we will remove it.
Changes
When this policy changes we update the date below. If a change matters to you, such as a new processor or a different purpose, we say so on the site rather than hoping you re-read the page.
Last updated
9 September 2026.