Unchecked chronic stress can lead to health conditions such as heart disease and mental disorders. Catching rising stress levels early is important, but daily blood tests at a doctor’s office aren’t feasible for most people, and self-reported questionnaires are subjective. That’s why researchers are developing point-of-care tests that measure cortisol levels in saliva, which mirror the hormone’s concentrations in blood.

Although the saliva tests are promising, many of them require people to remember to perform the complicated analyses or use a bulky mouthguard. In addition, the anxiety of performing a test can cause stress levels to spike. So, Sameer Sonkusale and colleagues took a completely different approach by integrating a cortisol sensor into a dental floss pick—something many people use every day.