FDA warns against smartwatches, rings that claim to measure blood sugar without needles

Smartwatches and rings that claim to measure blood sugar levels for medical purposes without piercing the skin could be dangerous and should be avoided, the U.S. Food and Drug Administration warned Wednesday.

The caution applies to any watch or ring, regardless of brand, that claims to measure blood glucose levels in a noninvasive way, the agency said. The FDA said it has not authorized any such device.

The agency's notice doesn't apply to smartwatch apps linked to sensors, such as continuous glucose monitoring systems that measure blood sugar directly.