Apple Health and Libre connection

When you read the write up by App developer on these app, none of these apps show compatibility with the iOS Health App.

FreeStyle Libre 3 – US on the App Store

FreeStyle Libre 2 - US on the App Store

FreeStyle LibreLink - US on the App Store

At the same time, the Blood Glucose Section in the Health shows few Apps, and Freestyle Libre is not one of them.

What could work

• The Libre 3 system (sensor + app) is meant to work when sensor and app come from the same region.  
• If you purchased Libre 3 sensors in the US and installed the US version of the app (on a smartphone whose account is set to the US), and then travel or move to another country — in principle you could carry on using those very sensors & that app (assuming your phone meets the technical OS requirements).  

What might break (or not work at all)

• Many regulatory-locked CGM systems (including Libre) have restrictions: sensors and apps are often notinterchangeable between regions. If region codes don’t match, the app may refuse to associate with the sensor.  
• If the official version of the app isn’t available in your “new” country’s app store, you may not be able to update it — or even download it — unless you keep your old account/region setting.  
• Even if you “hack around” app-store restrictions (e.g. via VPN or side-loading), it may or may not work reliably. Several users report “incompatibility” errors or that when they tried using a sensor from country A with an app from country B, it failed.  
• Official support from the manufacturer may be void if you are outside the intended region.  

What this means in practice if you buy Libre 3 in the USA and then move/use in India

• If you keep your US-based phone settings (Apple ID or Google Play region set to USA) and keep using the same US Libre 3 app and US sensors, there is a decent chance it could work (some users in online forums say it “worked fine” when travelling to India).  
• But if you change your Apple ID or phone region to India (so you use the Indian App Store / Google Play), there’s no guarantee the app will still “accept” USA-purchased sensors. Many anecdotal reports suggest it will fail due to region lock.  
• Even if you get it to work, you may not be able to purchase replacement sensors in India (if Libre 3 is not officially available there). And manufacturer support or warranty may be invalid.