Sustain — Privacy Policy

Sustain is built privacy-first. Your health information lives on your device by default, we never sell your data, and health data is never used for advertising.

The short version: What you log stays on your iPhone. Optional features (AI coaching, iCloud backup, analytics) are opt-in, minimized, and de-identified. You're always in control.

Who we are

Sustain ("we", "us") is operated by Vexai LLC, 2218 Jackson Blvd, Ste 5, Rapid City, SD 57702, USA. Questions: chahat.b@everis.ai.

Information you enter

Weight, body composition, food and nutrition logs, medications and doses, symptoms, food-noise ratings, and progress photos are stored locally on your device using Apple's on-device database. If you turn on iCloud sync, this data is backed up to your own private iCloud account — we cannot access it. Progress photos never leave your device.

Apple Health

With your permission, Sustain reads weight and body-composition data from Apple Health to show trends, and can write weight and nutrition back. This happens on your device. Health data is never used for advertising and is never sold. You can revoke access anytime in the Health app.

AI features (optional)

When you use the AI coach, insights, or reports, we send a small, minimized and de-identified summary of your signals (for example, your phase and protein progress) to our AI processor, Anthropic, through our own secure server. We do not send your name or your raw logs. When you choose to scan a food or estimate body fat from a photo, that single image is sent for analysis only at your request and is not stored afterward.

Purchases

Subscriptions are processed by Apple and managed via RevenueCat. We receive your subscription status (active/expired), not your payment details.

Analytics (optional)

If enabled, we collect anonymous product-usage events (e.g., which screens are used) via PostHog to improve the app. This never includes your health data and can be turned off in Settings.

What we never do

Sell or rent your personal or health data.
Use health data for advertising or share it with advertisers.
Send your raw logs, name, or photos to third parties for marketing.

Data sharing summary

Data	Where it goes
Health & food logs, photos	Your device (and your private iCloud if you enable sync)
De-identified AI signals	Anthropic, via our server, only when you use AI features
Subscription status	Apple / RevenueCat
Anonymous usage events	PostHog, only if analytics enabled

Retention & deletion

Delete individual entries in the app anytime, or remove all data by deleting the app. To request deletion of anything held on our side, email chahat.b@everis.ai.

Your rights

Depending on where you live (including under GDPR and CCPA), you may have rights to access, correct, delete, or export your data. Contact us and we'll help. We do not sell personal information.

Children

Sustain is intended for adults (17+) managing their health with a clinician. It is not directed at children.

Not medical advice

Sustain provides general wellness and nutrition information only. It is not a medical device and does not diagnose conditions or recommend medication or dosing. Always consult your healthcare provider.

Changes

We'll update this page and revise the date above when our practices change.