Trendline is an iPhone app that reads Apple Health. Everything below assumes an iPhone; the destination for your readings is Apple Health, which Android does not run.
First: make sure you're in the right Renpho app
There are two Renpho apps on the App Store, and the difference matters more than anything else on this page. The original app is now literally named "Renpho - Outdated Version" — its listing says it can no longer register data and asks users to switch. The current app is RENPHO Health (a separate listing, from developer Joicom corporation). If your weigh-ins stopped appearing anywhere, or Apple Health shows a Renpho source that went quiet, check which app icon you've been tapping before you troubleshoot anything else. Both listings were live and read as described on the review date above.
Renpho's own migration guide covers moving between the two: log in to RENPHO Health with the same email you used in the old app, and your measurement history transfers to your new account automatically (Renpho's sync guide). That transfer is between Renpho accounts — it is a separate question from what reaches Apple Health, which we'll get to.
What RENPHO Health writes to Apple Health
Per the HealthKit description on the RENPHO Health App Store listing, the app synchronizes weight, body fat percentage, BMI, lean body mass, height, and resting energy to Apple Health. That's a comparatively generous list for a budget-tier scale app — many competitors write weight alone. The rest of the numbers on the scale's readout (body water, bone mass, visceral fat, muscle-mass-as-its-own-line) stay inside the Renpho app, because Apple Health has no types for them.
Turning the sync on
Two paths, both ordinary:
- At first launch: when RENPHO Health first asks for Health access, iOS shows the standard permission sheet listing each data type. Grant the categories you want written. If you dismissed that sheet once, it will not chase you — use the second path.
- Any time after: Renpho's FAQ documents the Health-app side: open Apple Health, tap your profile icon on the Summary tab, find the privacy section and tap Apps, select the Renpho app, and tap "Turn On All" — or enable just the types you want (Renpho Health App FAQ). The same switches live in iPhone Settings under Apps → Health → Data Access & Devices.
One boundary to state plainly, because no vendor states it for you: readings flow from the day you enable it, forward. Renpho does not document whether past readings transfer to Apple Health when you first grant access — so we don't claim it. If your history predates the toggle and it matters to you, check Health after enabling rather than assuming.
The account question, honestly
RENPHO Health lets you skip registration and use Guest Mode. The tradeoff is documented by Renpho itself: in Guest Mode your measurement history lives only on that phone — it cannot be transferred, and it's gone if you uninstall the app or change devices (Renpho's sync guide). With a registered account, readings are backed up to Renpho's servers (FAQ).
This is exactly where Apple Health earns its keep, whichever you choose. A weigh-in that RENPHO Health has written to Apple Health belongs to your phone's health record — it survives app reinstalls, account confusion, and any future app-generation shuffle like the one that orphaned the original Renpho app. Guest Mode plus Health sync is a legitimately private setup; just know that the in-app history is the disposable copy and Health is the durable one.
What lands where
| What RENPHO Health writes to Apple Health | What Apple Health can store | What Trendline reads from Health |
|---|---|---|
| Weight, body fat %, BMI, lean body mass, height, resting energy (per the App Store listing's HealthKit description). Body water, bone mass, visceral fat and muscle mass stay in the Renpho app. | Weight, BMI, body fat %, lean body mass, height, waist circumference. No types exist for body water, bone mass, or visceral fat. | 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. |
When Trendline launches, it will also accept manual entries — including composition values Apple Health has no type for, like visceral fat and body water — so the numbers Renpho keeps to itself can still sit alongside your trend.
When sync stalls
The measurements pipeline has three links — scale → app → Health — and each fails differently:
- Scale → app: Renpho's FAQ walks the Bluetooth cases: iOS requires per-app Bluetooth permission (Settings → Apps → Renpho Health → Bluetooth), and the vendor's reset sequence is pulling a battery for a few seconds, rebooting the phone, forgetting the device in the app's Device tab, and re-pairing (FAQ). The scale itself stores up to 20 weigh-ins offline and uploads them on the next connection — so a missed morning usually isn't lost, it's waiting.
- App → Health: re-check the permission switches in Health (profile → Apps) or iPhone Settings. A category toggled off writes nothing, silently.
- Wrong app entirely: if you're still in "Renpho - Outdated Version," no amount of toggling helps — its own listing says it can't register data. Migrate first.
Try the idea
Renpho's app does include an export function (FAQ: History → Export data). Paste a few weeks of weigh-ins into the free weight trend calculator — it runs in your browser, nothing uploads — and compare the raw series against a deliberately slower signal. Day-to-day variation is real without being informative; the slower line is the part worth watching.
Sources
- App Store: RENPHO Health (HealthKit description)
- App Store: Renpho - Outdated Version
- Renpho: FAQ for the Renpho Health App
- Renpho: "Can't Sync Your Data to the Renpho Health App? Here's How!"
- Apple: view your health data on iPhone
Trendline is not affiliated with or endorsed by Renpho. Vendor behaviors change; this page states what was verifiable against the sources above on July 20, 2026.