iHealth scales sync to Apple Health through the iHealth MyVitals app, and the enable path is vendor-documented: Account, Authorize 3rd Party Apps, Apple Health, Authorize. Everything routes through an iHealth cloud account first. iHealth says "measurement data" syncs after authorization but doesn't enumerate which types.
Trendline is an iPhone app that reads Apple Health. Everything below assumes an iPhone; the destination for your weigh-ins is Apple Health, which Android does not run.
The shape of the pipeline
iHealth's wireless scales (Nexus and Nexus Pro, per iHealth's compatibility list) pair with one app, iHealth MyVitals (iHealth Labs Inc.; 4.8 stars across 163K ratings when we checked on October 18, 2026). The App Store listing states the Apple Health side directly: "After authorization, you can sync your measurement data in this app to your Healthkit to conduct comprehensive health data monitoring and health management." So the pipeline is scale → MyVitals → Apple Health — the same three links as every brand on our smart-scale index, with one distinctive middle: iHealth's link runs through its cloud.
The account, plainly
This is the part the flagship brands get criticized for, and iHealth documents it without apology. The same listing: "By creating an iHealth account and connecting our devices, you'll be able to store data securely in the cloud." The vendor's own sync-troubleshooting article makes the dependency concrete: its first step is checking that you're signed in with the correct account — noting that "many users don't realize they created an extra account" — and it states that a stable Wi-Fi or mobile data connection "is required for syncing" (iHealth support). Older iHealth docs describe synced data being sent to "your iHealth cloud secure space" (support article). In short: iHealth stores measurement history in the cloud under an iHealth account, and the docs assume you have one.
Two more vendor-stated facts sharpen why the Apple Health copy matters. The troubleshooting article warns that once a measurement transfers from the device to the app "it is erased from the device and cannot be recovered," and that on iPhone, clearing cache or reinstalling the app "deletes all stored data" locally. A weigh-in that MyVitals has also written to Apple Health is a separate copy: it is stored in Apple Health, outside those app-side deletions. (Apple notes that Health data can also sync through iCloud to your other devices on the same iCloud account.)
Turning Apple Health sync on
Unusually for this cluster, the enable path is vendor-documented, step by step (iHealth support, updated 2025):
Open iHealth MyVitals and tap Account in the lower right corner.
Under DATA, select Authorize 3rd Party Apps.
Choose Apple Health, tap it, then tap Authorize and confirm with Done.
The same article notes the connection is reversible from the same screen (the button reads Unauthorize once linked), and that iHealth's article names Apple Health and Fitbit as its two third-party integrations. iOS will present its standard permission sheet along the way; grant the categories you want written. The switches also live in Apple Health itself — profile icon → Apps → iHealth — and in iPhone Settings → Apps → Health → Data Access & Devices (Apple's guide).
What's documented to transfer — and what isn't
iHealth says "measurement data" syncs to Apple Health after authorization; nowhere we could find does it enumerate which data types. Weight is the safest expectation: the App Store listing says the app supports weighing scales, and weight has an obvious Health type. iHealth's composition-capable scales estimate further values, and the vendor's profile FAQ notes body-composition scales use your profile details to calculate them (iHealth support) — but whether any composition value is written to Health is not vendor-documented, so we won't claim it. The iOS permission sheet at authorization time is your authoritative list: whatever types it names are what MyVitals can write on your install.
What lands where
| What MyVitals writes to Apple Health | What Apple Health can store | What Trendline reads from Health |
|---|---|---|
| Vendor-confirmed in general terms: "measurement data" syncs after authorization (App Store listing), with a documented enable path (support article). No official per-type list exists; expect weight, and check the iOS permission sheet for the rest. | Weight, BMI, body fat %, lean body mass, height, waist circumference. No body-measurement types exist for body water percentage, protein percentage, visceral fat, or similar composition estimates (Apple's water and protein types are for dietary intake, per Apple's HealthKit type list). | Weight, body fat %, and lean body mass (height as context). BMI and waist are not imported — BMI is derivable, and neither carries trend information Trendline needs. |
Trendline also accepts manual weight and body-fat entries and clinic-scan reports, which can hold composition values Apple Health has no type for, such as body water and visceral fat. Readings the cloud keeps to itself can still sit alongside your trend.
iHealth scale not syncing to Apple Health?
iHealth publishes a general sync-troubleshooting sequence, and it starts where the architecture starts (vendor article): confirm you're signed in with the right account, confirm Bluetooth is on and the device paired, confirm the internet connection, restart the app, and replace weak batteries. It also warns against clearing cache or reinstalling on iPhone before a sync completes, because local data doesn't survive that.
For the Apple Health link specifically, iHealth's closest published fix is filed under its activity trackers, not its scales — we label it accordingly: open Apple Health, tap your profile picture, select Apps under Privacy, open iHealth, and make sure every data category is toggled on (vendor article). The permission-rebuild step generalizes to any HealthKit app; the article's device specifics don't. If readings exist in MyVitals but not in Health, permissions are the first suspect; if they never reached MyVitals, the problem is upstream of Health entirely.
And the boundary no vendor states for you: iHealth does not document whether past measurements transfer to Apple Health when you first connect, so we claim neither a backfill nor forward-only transfer. If your MyVitals history predates the toggle, check Health after enabling rather than assuming.
Try the idea
Once a few weeks of weigh-ins are flowing — or while you're still untangling accounts — paste your readings into the free weight trend calculator. It runs in your browser, nothing uploads, and it draws a deliberately slower signal next to your raw measurements. Day-to-day variation is real without being informative; the slower line is the one worth watching.
Questions people ask
How do I sync my iHealth scale with Apple Health?
Open iHealth MyVitals and tap Account in the lower right corner. Under DATA, select Authorize 3rd Party Apps, choose Apple Health, tap Authorize, and confirm with Done. iOS also presents its standard permission sheet, where you grant the categories you want written.
Do I need an iHealth account to sync to Apple Health?
iHealth's documentation assumes you have one. Its listing says creating an account and connecting devices stores data in the cloud, and its sync-troubleshooting article starts by checking that you're signed in with the correct account.
What does iHealth write to Apple Health?
iHealth says "measurement data" syncs after authorization, and nowhere we could find does it enumerate which data types. Weight is the safest expectation. The iOS permission sheet at authorization time is your authoritative list.
Why isn't my iHealth scale syncing to Apple Health?
iHealth's general sequence: confirm you're signed in with the right account, confirm Bluetooth is on and the device paired, confirm the internet connection, restart the app, and replace weak batteries. Avoid clearing cache or reinstalling on iPhone before a sync completes, because local data doesn't survive that.
Will my past iHealth readings transfer to Apple Health?
iHealth does not document whether past measurements transfer to Apple Health when you first connect. Check Health after enabling rather than assuming.
Sources
- App Store: iHealth MyVitals (HealthKit statement, account and cloud description)
- iHealth support: how to authorize 3rd-party apps in MyVitals (iOS)
- iHealth support: why is some data missing or not syncing
- iHealth support: activity data is not being shared with Apple Health
- iHealth support: what is the iHealth MyVitals app
- iHealth support: which devices pair with MyVitals
- Apple: view your health data on iPhone
- Apple: manage Health data
- Apple: HealthKit quantity type identifiers
Trendline is not affiliated with or endorsed by iHealth Labs. Vendor behaviors change; this page states what was verifiable against the sources above on October 18, 2026, and says so where the documentation runs out.