# A prototype ring reads blood sugar from finger sweat

Source: https://idevice.com/this-sweat-reading-ring-tracks-blood-sugar-without
Published: 2026-07-29

> A UC San Diego prototype ring reads glucose and ketones from finger sweat, matching a continuous monitor in trials but running half the hours it would need.

Engineers at UC San Diego have built a prototype ring that reads chemistry rather than pulses. Described in Nature Communications on July 23 and named CHARM, it uses an osmotic hydrogel to pull small amounts of sweat from the finger passively, with no exercise needed, then runs it through an electrochemical sensor array that tracks four biomarkers at a time out of glucose, ketones, lactate, uric acid, vitamin C and alcohol. 9to5Mac draws the line plainly: commercial rings read biophysical measures like heart rate and sleep, and this reads molecules.

In trials including people with Type 1 diabetes, the sweat readings closely matched a continuous glucose monitor for glucose and a blood meter for ketones. "The ring’s ability to track both glucose and ketone continuously and simultaneously would greatly benefit optimal insulin dosing for the management of diabetes," said Joseph Wang, one of the UC San Diego researchers. It runs 12 hours where the team says 24 would be needed for the readings to be clinically useful, the hardware is still bulky, and Gizmodo notes it has yet to be validated comprehensively. A waterproof version is in progress.