If you’ve ever had a bad case of jet lag, you know how a disruption to your body’s circadian rhythm makes it difficult to function. Molecular circadian “clocks” exist in cells throughout the body, governing more than just sleep and wake cycles—they are crucial to many aspects of human health. For more than a decade researchers have been trying to figure out what makes them tick, in search of new insights into diseases like Alzheimer’s, cancer and diabetes.