FDA reminds world that it has yet to OK smartwatches for noninvasive glucose monitoring

The FDA issued a safety communication this week warning Americans that if they see a smartwatch or smart ring claiming to offer noninvasive blood sugar monitoring, the agency had nothing to do with it, thank you very much.

Though quite a few technology developers—of both the medtech and broader Big Tech varieties—are currently working toward building portable devices that can accurately measure glucose levels without having to pierce the skin, none have yet to pass the FDA’s muster.

The regulator didn’t call out any specific peddlers of the unauthorized devices in its notice, but said they’re “manufactured by dozens of companies and sold under multiple brand names.”

The notice warned that since the devices’ safety and efficacy haven’t been reviewed or verified by the agency, they may provide inaccurate blood sugar readings. Those inaccuracies could in turn lead to “errors in diabetes management,” including taking an unnecessarily high dose of insulin or other glucose-lowering medication, which can result in “mental confusion, coma, or death within hours of the error,” per the FDA.

In short, the agency said, patients and their caregivers should not buy any smartwatches or smart rings that claim to offer noninvasive glucose monitoring, and healthcare providers should discuss with their patients the risks of using such unauthorized products while pointing them instead to FDA-cleared diabetes management devices if needed.

The FDA did take care to distinguish between these “smart” devices that allegedly collect blood sugar readings themselves and actually authorized continuous glucose monitors—which do still have to pierce the skin—that connect to smartwatches to display their data.

The agency’s stark reminder comes in the wake of a flurry of updates in the last year about the race to develop the first agency-approved noninvasive glucose sensors, the most recent of which saw Samsung announce its entry into that race.

In an interview with Bloomberg last month, the head of the company’s digital health team said they’re putting “significant investment” toward adding both noninvasive glucose sensing and continuous cuffless blood pressure monitoring to the Galaxy family of smartwatches and smart rings. Though the executive, Hon Pak, M.D., didn’t offer a concrete timeline for the additions, he expressed hope that glucose tracking could arrive on the devices within the next five years.

Samsung will be competing in that arena against Apple, which has long been rumored to be working on adding noninvasive blood sugar monitoring to its Apple Watches. A report early last year claimed that the tech giant's attempt had recently reached “major milestones” bringing it to the proof-of-concept stage, though Apple declined to confirm or deny the report.

Elsewhere, both Rockley Photonics and Know Labs have already touted study results of their own respective forays into needle-free glucose monitoring. Rockley’s miniaturized technology, which would be housed in a smartwatch-style wearable, was able to measure glucose levels with an accuracy of 5 mg/dL, according to results shared by the company in September.

Know Labs, meanwhile, unveiled last summer the first prototype of its Generation 1 glucose-sensing device, which is meant to be carried in a user’s pocket and held in the palm to collect on-demand blood sugar readings. A month later, the company shared data showing that its technology was able to generate readings within about 11% of those collected by a Dexcom G6 CGM, a significant improvement over the 20% gap it had reported just a few months before.