But rather than a gym-soaked t-shirt, it needs just one millionth of a litre of sweat to do the testing.
The team - in South Korea - showed the sensor was accurate and think it could eventually help patients with diabetes.
And in extra tests on mice, the sensor was hooked up to a patch of tiny needles to automatically inject diabetes medication.
The team at the Seoul National University were trying to overcome the need for "painful blood collection" needed in diabetes patients.