Smart rings could be heading towards a new generation of health monitoring, with researchers developing a prototype capable of continuously analysing chemical biomarkers via sweat.

The device, called CHARM (Continuous Health Analyzing Ring Module), has been developed by engineers at the University of California San Diego and is designed to monitor multiple biomarkers directly from sweat collected from the finger.

While current smart rings mainly monitor metrics like heart rate, sleep and skin temperature, CHARM is designed to track the body’s underlying biochemical activity.

The prototype can monitor glucose, ketones, vitamin C, uric acid, lactate and alcohol, although it can measure a maximum of four biomarkers simultaneously. The findings have been published in the journal Nature Communications. 

The technology does not require users to exercise or otherwise produce significant amounts of sweat. Instead, using an osmotic hydrogel, CHARM passively draws sweat from the skin, which then goes through a mini sensor inside the ring.

The ring then wirelessly transmits the data to a connected device, which allows for the wearer’s biomarker levels to be monitored in real time.

Researchers say the technology could eventually provide consumers with a more convenient way to monitor aspects of metabolic health, nutrition and exercise. Glucose and ketone monitoring could also have potential applications in diabetes management, although the researchers assert that the prototype has not been evaluated for insulin dosing or closed-loop therapy. 

The prototype weighs 5.1 grams and measures approximately 3cm in diameter. The sensors, electronics and flexible battery are all integrated into the ring structure. Its battery can operate for more than 12 hours before needing a recharge. 

One of the most significant aspects of the research is that it shows the finger can be used as a practical location for continuous sweat analysis. Potentially, biochemical monitoring could be incorporated into the same discreet form factor that has helped drive the popularity of smart rings.

So what’s next? CHARM is currently a research prototype rather than a commercially available consumer product. Researchers say further testing and validation across larger and more diverse groups will be required, while improvements are also needed to enable longer-term sweat extraction and to make the device more waterproof. 

The researchers are also looking at combining biochemical sensing with additional physical health measurements, potentially creating future smart rings capable of monitoring a broad range of body signals.