The US Food and Drug Administration (FDA) has issued a safety communication to warn consumers, patients, caregivers, and health care providers of the dangers of using smartwatches or smart rings that claim to measure blood glucose levels (blood sugar) without piercing the skin. These devices are different from smartwatch applications that display data from FDA-authorized blood glucose measuring devices that pierce the skin, like continuous glucose monitoring devices (CGMs).

The FDA has not authorized, cleared, or approved any smartwatch or smart ring that is intended to measure or estimate blood glucose values on its own. For people with diabetes, inaccurate blood glucose measurements can lead to errors in diabetes management, including taking the wrong dose of insulin, sulfonylureas, or other medications that can rapidly lower blood glucose. Taking too much of these medications can quickly lead to dangerously low glucose, leading to mental confusion, coma, or death within hours of the error.

The regulator said the only wrist-worn devices currently approved for diabetes management are those that connect to an FDA-cleared continuous glucose monitor with a sensor inserted under the skin.

The claims and techniques of unauthorized devices

Sellers of these smartwatches and smart rings claim their devices measure blood glucose levels without requiring people to prick their finger or pierce the skin. They claim to use non-invasive techniques, such as optical, thermal, or electrical sensors. However, these techniques have not been proven to be accurate or reliable for measuring blood glucose levels.

These smartwatches and smart rings do not directly test blood glucose levels. Instead, they use algorithms to estimate blood glucose values based on other factors, such as heart rate, skin temperature, or electrical conductivity. These estimates may not reflect the actual blood glucose levels in the body, and may vary depending on the device, the user, the environment, or other conditions.

These smartwatches and smart rings are manufactured by dozens of companies and sold under multiple brand names. This safety communication applies to any smartwatch or smart ring that claims to measure blood glucose without piercing the skin, regardless of manufacturer or brand.

The recommendations and actions of the FDA

The FDA advises consumers, patients, caregivers, and health care providers to follow these recommendations:

Do not buy or use smartwatches or smart rings that claim to measure blood glucose levels. These devices may be sold through online marketplaces or directly from the seller. Be aware that the safety and effectiveness of these devices have not been reviewed by FDA, and the use of these devices could result in inaccurate measurements of blood glucose levels.
If your medical care depends on accurate blood glucose measurements, talk to your health care provider about an appropriate FDA-authorized device for your needs.
Report any adverse events or problems with smartwatches or smart rings that claim to measure blood glucose levels to the FDA’s MedWatch program.

The FDA routinely monitors the medical device market and became aware of unauthorized products being marketed to consumers. The agency is working to ensure that manufacturers, distributors, and sellers do not illegally market unauthorized smartwatches or smart rings that claim to measure blood glucose levels. Additionally, the FDA is alerting consumers about this issue and making the public aware that smartwatches and smart rings should not be used to measure blood glucose levels.