Many aspects of modern life, including screen use and shift work, can confuse the body’s natural sleep and wake cycle. Up to 19% of adults in the U.S. report not getting enough rest or sleep every day. Chronic lack of sleep can harm both your mental and physical health. A range of chemicals and hormones circulate in the body to help control when and for how long people sleep. One such hormone, melatonin, is produced by a gland within the brain in response to darkness. It helps cue the body that it’s time to sleep. Melatonin is sold as an over-the-counter dietary supplement in a range of doses. But studies to date have not consistently shown that taking melatonin supplements helps with insomnia, jet lag, or recovery from shift work. It may provide some benefits for people with less-common sleep disorders caused by problems with the body’s internal clock. But …