For kids, temporary tattoos are a fun way to pretend you’re a real grown up. But do they have actual practical uses for adults? Graduate students at the University of California, San Diego have now developed a possible life changing use for the disposable technology, producing a temporary tattoo for diabetics that monitors their blood glucose levels and avoids the need for the usual daily finger prick tests. The devices work thanks to miniature, non-invasive technology that’s emedded in the tattoo itself. A pair of precisely patterned electrodes are printed onto the temporary tattoo paper, which is applied to the skin and applies a very mild electrical current. This process enables tiny sensors on the tattoo to detect glucose levels and output the data.