Marrow is a free calorie counter and fitness tracker that also puts every Apple Health metric in one place, and gives all of it back to you as files, automations, or a live connection to your AI. No account, no ads, no subscription required.
EVERY METRIC, NOT A CURATED FEW
Marrow reads 172 Apple Health data types: steps, heart rate, HRV, sleep stages, blood oxygen, respiratory rate, walking steadiness, body composition, cycle tracking, and the long tail Apple never puts in a chart. Add its own meal diary and strength log and you are tracking 178 data series in one place. If your watch or a connected app records it, Marrow shows it, with daily, weekly, and monthly trends.
FOOD LOGGING THAT IS ACTUALLY FAST
Photograph a meal and get a nutrition estimate you review and edit before it is logged. Scan a barcode. Or search a USDA food database built into the app, which works with no signal at all. Marrow tracks 39 nutrients per meal, not just calories, and writes it all back to Apple Health.
WORKOUTS, STRENGTH AND CARDIO
Log sets and reps against an exercise catalog, or record cardio and see the route. Workout history sits next to the health metrics it moved, so you can see what your training is actually doing.
WIDGETS
Today's calories and macros, your daily statistics and one-tap logging on the Home Screen, plus Lock Screen widgets.
YOUR DATA LEAVES WHEN YOU WANT IT TO
Export CSV, JSON, or GPX. Schedule automations that post to a server you choose. Pair your own self-hosted mirror. Marrow was built by someone who got tired of health data being trapped in an app that would not give it back.
BUILT FOR AI, IF YOU WANT IT
Marrow can serve your health data over the Model Context Protocol, so Claude, Cursor, or any MCP client can read it with a token you control. It ships turned off, runs on your own device, and costs nothing.
MARROW PRO, OPTIONAL
Everything above is free and stays free. Marrow Pro adds the parts that cost us to run: unlimited AI logging (photo, text and voice; free includes 3 a day), Connect your AI (a private hosted copy that ChatGPT, Claude or Gemini read any time and, if you allow it, log to when you ask: meals, workouts, sleep and more; every sign-in is approved from your phone), and campus dining hall menus. Monthly or yearly with a 7-day free trial, or a one-time lifetime purchase; prices are shown in the app. Subscriptions renew automatically until cancelled in your Apple ID settings; cancel during the trial and you pay nothing.
WHAT MARROW DOES NOT DO
No account. No ads. No analytics or tracking SDKs. No selling data. No subscription required. Your health data stays on your iPhone unless you deliberately send it somewhere, and the app makes it obvious when that happens.
Requires iOS 17 or later and Apple Health.
Marrow is a wellness tool. It does not diagnose, treat, cure, or prevent any condition, and it does not give medical advice.
Privacy Policy: https://marrowhealthapp.com/privacy
Terms of Use: https://marrowhealthapp.com/terms
