Melatonin is a hormone that our pineal gland secretes to tell the body that it’s time to wind down for sleep. The amount of melatonin you produce depends on a number of factors, with the biggest being your exposure to light. Melatonin levels usually rise after sunset (hence its nickname “the hormone of darkness”) and fall when the sun rises in the morning, which helps your body wake up.
People who use bright lights or technology at night, or need to stay awake during the evenings for work or travel, might find that their melatonin levels are out of whack, causing them to feel wide awake when they should be asleep. This is where melatonin supplements usually come in. “Melatonin is really helpful as a ‘chronobiological agent’ to adjust the sleep cycle,” explains Nishi Bhopal, M.D., a psychiatrist specializing in sleep medicine.
Bhopal notes–and other experts agree–that increasing melatonin levels through supplementation can be helpful for correcting a temporary disruption in your sleep-wake cycle, like when you’re traveling to a new time zone or acclimating to a night shift at work. In other words, it can make it easier for you to fall asleep at a new time. But once you get your sleep schedule back on track, it’s best to stop taking the hormone, as consuming melatonin nightly–especially in high doses–is not recommended.