Trendline is an iPhone app that reads Apple Health. This page covers getting eufy readings into Health; why Health is the right destination at all is its own page.
How to turn the sync on
The switch lives in the eufy Life app: open the Me tab, scroll down, and choose the Apple Health connection option (eufy's support article, which lists the Smart Scale T9140, C1, P2, P2 Pro, and P3 as supported). iOS will show the standard Health permission sheet; grant the categories you want written.
Per the app's own App Store disclosure, eufy Life synchronizes five measurement types to Apple Health after each weigh-in: weight, body fat percentage, BMI, lean body mass, and height (eufy Life App Store listing, checked July 2026). Everything else the scale estimates — body water, visceral fat, and the rest — stays in the eufy app, because Apple Health has no type for those metrics.
The open-app catch
On Bluetooth models, the reading reaches your iPhone only while the eufy Life app is open. Reviewing the Bluetooth-only C20 in October 2025, 9to5Mac put it plainly: "data is only sent to the iPhone when the Eufy app is open" and you step on the scale (9to5Mac). The same review notes the scale holds weigh-ins locally and hands the stored measurements over the next time the app connects — so readings taken with your phone in another room aren't lost, but they don't appear in Apple Health until you open the app near the scale again.
Practical habit: open eufy Life before you step on. The transfer and the Health write then happen in the same motion as the weigh-in.
Wi-Fi-capable models (such as the P3) may behave differently, since they can upload without a phone in the room — we have not verified their Apple Health timing and won't claim it here.
One user leaves; the family stays
eufy's support documentation states the second rule directly: "Only the data under the main user can be synced to these apps" (same article). Family members' weigh-ins stay inside the eufy app — they never reach Apple Health from a shared account. The vendor's recommended arrangement is for each person to register their own eufy Life account, on their own phone, so each account's main user syncs to that phone's Health store. If a family member's readings have been silently missing from their Health app, this is the documented reason.
Anyone whose readings can't make the trip can still add a reading to Apple Health by hand — a manual entry has the same standing in Health as a synced one.
When sync breaks: the vendor's own fix
eufy publishes a reset procedure for a paired scale whose measurements stop arriving in Health: open your Apple Health connection settings, turn off all the categories to disconnect it from your eufy account, then reconnect (eufy's troubleshooting article). If that doesn't restore the flow, the article asks you to contact support with a short video of the failure. Restarting the eufy Life app and cycling Bluetooth on both phone and scale are the usual companion steps.
Readings that already landed in Apple Health are unaffected by any of this — once written, they belong to Health, not to the eufy app.
What lands where
| What eufy Life writes to Apple Health | What Apple Health can store | What Trendline reads from Health |
|---|---|---|
| Weight, body fat %, BMI, lean body mass, height (App Store listing, July 2026) | Weight, body fat %, lean body mass, BMI, height, waist circumference | Weight, body fat %, lean body mass — with height as context. BMI and waist are not imported. |
When Trendline launches, it will also accept manual entries for the composition values Apple Health has no type for — the body water and visceral fat numbers that currently live only in the eufy app.
Try the idea
Once a few weeks of weigh-ins are flowing, the raw series will bounce — that's variation, not a broken scale. Paste your readings into the free weight trend calculator and compare them against a deliberately slower signal; the direction underneath is the number worth watching.
Sources
- eufy support: syncing with Apple Health, Google Fit, and Fitbit (enable path, supported models, main-user rule)
- eufy support: what to do if the app doesn't sync with Apple Health (disconnect/reconnect fix)
- 9to5Mac (Oct 2025): logging weight to Apple Health with a eufy smart scale (open-app requirement, C20)
- eufy Life on the App Store (HealthKit data types)
Trendline is not affiliated with or endorsed by eufy or Anker Innovations. Vendor behaviors change; everything above was verified against the linked pages on July 20, 2026.