An apparent Apple Watch Series 10 prototype with a significantly different health sensor surfaced online Monday. Speculation suggests the prototype version might indicate work on advanced health monitoring capabilities like blood glucose monitoring — an Apple goal for many years.
Apple Watch 10 prototype reveals possible blood glucose monitoring sensor
The images, shared by Apple prototype collector “Stella-Fudge” (also known as “Choco_bit”) on X, reveal a circular sensor arrangement on the back of the device. It departs dramatically from the configuration found on production Apple Watch Series 10 models. While the final product features larger, more spaced-out sensors, this prototype sports notably smaller sensors concentrated in the center of the sensor glass.
Could part of the sensor array be for blood glucose monitoring? This longstanding Apple Watch goal came up recently amid news that Apple wants to put an AI health coach on its devices.
Perhaps most intriguingly, the prototype includes an additional ring of lights around the perimeter of the sensor area. The purpose of this ring remains unknown, but its presence suggests Apple was testing enhanced health monitoring capabilities.
“A very unique health sensor arrangement,” Stella – Fudge wrote. “The health sensors got shrunk down a lot and there was an extra light ring around the perimeter.”
In a comment on the original post, Stella – Fudge added,”At this time I don’t know what the extra sensor is for but a test platform for blood sugar is a likely possibility.”
The goal of blood glucose monitoring
Prototype Apple Watch Series 10 with… A very unique health sensor arrangement.
The health sensors got shrunk down a lot and there was an extra light ring around the perimeter. The watch is also running an unreleased build of watchOS11, somewhere between 11.1b5 and 11.1rc. pic.twitter.com/8n06JkQT39
— Stella – Fudge (@StellaFudge) March 31, 2025
Blood glucose monitoring has long been rumored as a holy grail feature for Apple’s wearable lineup. Current glucose monitoring methods typically require invasive blood sampling, but Apple reportedly has been researching non-invasive approaches for years.
If Stella-Fudge’s speculation about this prototype being a test platform for blood sugar analysis is accurate, it would indicate Apple may have been closer to implementing this technology than previously believed.
Running on unreleased watchOS build
The prototype ran on an internal build of watchOS 11.1 (build number 22R5575x) that was never publicly released, positioned somewhere between watchOS 11.1 beta 5 and the watchOS 11.1 release candidate, according to Stella – Fudge.
But testing the prototype’s unique sensors isn’t possible because the necessary applications can only be retrieved from Apple’s internal network servers.
“Unfortunately theres no way to test the health sensors atm,” Stella – Fudge said. “Stock apps will not install since this build can only pull them off Apples internal network servers.”
More health monitoring on the way
Photo: Stella – [email protected]
This discovery comes amid ongoing reports that Apple continues to develop additional health-monitoring capabilities for future Apple Watch models. One such feature reportedly in development would alert users to signs of high blood pressure, though development challenges have delayed its implementation.
The final retail version of the Apple Watch Series 10 came out with modest upgrades. It featured a larger display and slimmer profile. The health sensors on production models measure heart rate and, outside the United States, blood oxygen levels (the latter feature being limited due to an ongoing patent dispute).
Good track record
As a known collector of Apple prototypes, Stella-Fudge has a solid track record. It tends to lend credibility to the authenticity of this device. While it’s impossible to confirm exactly what Apple was testing with this sensor configuration, its existence provides a glimpse into the company’s health technology research and development process.
Apple users hoping for advanced health features like blood glucose monitoring might need to wait for a while. The upcoming Apple Watch Series 11 might incorporate some new innovations. But whether the mysterious sensor design seen in this prototype will make it to production remains to be seen.
