Privacy policy

Who we are

Dosyne is published by Vast Flow, LLP, which operates the app and this website and is the data controller for the limited processing described here. Write to [email protected] with any question about this policy, including a request to access or delete data.

The short version

Dosyne has no user accounts, no sign-in and no cloud sync. It never asks for your name, your email address or your date of birth, and there is nowhere for it to send them. All of your data — logged doses, vials, injection sites, weights, settings — lives in the app's own storage on your device. Every calculation happens locally. Deleting the app deletes the data with it.

This is why the App Store privacy label reads Data Not Collected. That is not a formality we squeezed through; it is a genuine description of the architecture.

Why we built it this way

A record of what someone injected, when, and where on their body is about as sensitive as health data gets. It could be subpoenaed, breached, sold in an acquisition, or simply mishandled. The most reliable protection against all of those is not to hold it, so the app has no server that could be compromised and no database that could be breached. The cost is real: there is no cloud backup and no sync between your phone and your tablet. We think that trade is the right one for this category, and we would rather state the cost than pretend it does not exist.

What the app stores on your device

Logged doses with the compound name, amount and concentration at the time; vials and their remaining volume; injection-site history; weight entries; cycle plans; reminder settings; and non-sensitive preference flags. None of it is transmitted. It may be included in your own device backup if you have that enabled, in which case it is governed by Apple's or Google's terms rather than ours.

Apple Health

With your permission, the app reads body mass from Apple Health for the progress chart and mirrors weights you enter manually back into Health. That exchange is local to the device and governed by Apple's HealthKit rules, which prohibit using health data for advertising. We never receive it. You can refuse the permission and the app works normally without it, minus the chart. Note that iOS deliberately hides read-permission status from apps, so what we show you is our own intent rather than a confirmed connection.

Notifications

Reminders are scheduled locally by your device. There is no push server, no token, and nothing leaves the phone to make a reminder fire. Reminder text never contains an amount or a compound name, so a notification on a lock screen does not disclose anything to somebody glancing at it.

Purchases

Subscriptions are sold and processed by Apple and Google. We never see your payment details. To decide whether to unlock Pro features, the app uses RevenueCat, which processes an anonymous identifier and the receipt the store issues. That tells us a subscription exists and what state it is in. It does not identify you, and we cannot connect a subscription to a person or to any logged data.

Analytics: none in the app

The app contains no analytics SDK. No Firebase Analytics, no Crashlytics, no attribution SDK, no event tracking, no advertising identifier. We do not know which screens you open, which compounds you log, or how often you use it. This costs us product insight and we accept that.

This website is different and you should know it. It loads Microsoft Clarity, which records aggregate site usage — pages viewed, approximate region, device and browser, and anonymised interaction patterns such as scroll depth — so we can find pages that are broken or confusing. It is not connected to any app data and it does not follow you to other sites. It sets cookies and honours the Global Privacy Control signal where your browser sends one. A content blocker will stop it and every calculator on this site works normally without it.

The calculators on this site

Everything you type into a calculator here stays in your browser. Vial strengths, diluent volumes and amounts are never transmitted to us, because the arithmetic runs on your machine in JavaScript. Closing the tab discards it. There is no form submission anywhere on this website.

What we never collect

We do not collect your name, email address, contacts, photos, precise location, advertising identifier, or any health data. We do not sell data, we do not share it with data brokers, and there is no advertising in the app. There is no mechanism by which we could build a profile of an individual user, because there is no identity to attach one to.

Legal bases, for readers in the EEA and UK

Because the app processes personal data on the device rather than transmitting it to us, most of it never becomes processing we perform. Purchase-receipt validation is necessary to perform the contract you entered into when subscribing. Website analytics rest on our legitimate interest in improving a free resource, balanced against the fact that they do not identify you.

Retention

App data is retained on your device until you delete it or delete the app. We hold no copy and cannot retrieve or restore it — if you delete the app without a device backup, that history is gone, and we mention it here because people are sometimes surprised. Purchase records are retained for as long as store receipt validation requires. Website analytics follow Microsoft Clarity's own retention schedule.

Your rights

You may have the right to access, correct, delete or port your personal data, and to object to certain processing. In practice these are satisfied by the app itself: deleting an entry deletes it, and deleting the app deletes everything. If you want written confirmation of what we hold — which for an app user is a purchase receipt state and nothing more — write to [email protected] and we will respond within thirty days.

Children

Dosyne is not directed at children and we do not knowingly collect data from anyone under 13. Given the subject matter, the app is intended for adults.

Security

The strongest security property of this app is architectural: there is no account to compromise, no password to steal, no server to breach and no central database of user records to leak. Data on your device is protected by the operating system's own storage protections and by your device passcode. Website traffic is served over an encrypted connection.

International transfers

We hold no user data to transfer. Apple, Google, RevenueCat and Microsoft process data in the regions described in their own policies, which may include the United States, under the transfer mechanisms those providers publish.

Changes

If the way data is handled changes, this page changes and the date at the top changes with it. Material changes will also be announced in the app. If we ever added a server component, we would say so prominently rather than quietly amending a clause here.

Cookies and similar technologies

The app uses no cookies; it is not a browser. On this website the only cookies set are those used by Microsoft Clarity for the aggregate analytics described above. There is no advertising cookie, no remarketing pixel, no social login and no embedded third-party widget that could set one. The calculators store nothing in your browser beyond what the page needs while it is open, so closing the tab discards everything you entered.

We honour the Global Privacy Control signal where your browser sends one, and a content blocker or your browser's built-in tracking protection will prevent the analytics script loading at all. Every calculator on this site works normally without it.

If you are in California

We do not sell personal information and we do not share it for cross-context behavioural advertising as those terms are defined in the California Consumer Privacy Act. There is no advertising in the app at all. You have the right to know what we hold, to request deletion, and not to be discriminated against for exercising either — and because there is no account, exercising them usually requires nothing more than deleting the app.

A note on sensitive categories

A record of injections is sensitive personal data under several privacy regimes, and in some jurisdictions it attracts specific protections. The design answer we chose is the strongest one available: we do not receive it. Because the data never leaves your device, we hold no special category data about any user, we cannot be compelled to produce it, and no breach of our systems could expose it. If that ever changed we would say so prominently rather than amending a clause on this page.

Contact

Questions, deletion requests and complaints go to [email protected]. If you are in the EEA or the UK and are not satisfied with our response, you may complain to your national data protection authority.