According to Breus, people often think supplemental melatonin is a sleep initiator (aka that it makes you feel tired). But “to be clear,” he says, “melatonin is a sleep regulator, not a sleep initiator. Melatonin does not make you feel sleepy; it tells your body it’s bedtime. Those are two completely different processes in the brain.”
He explains that this results in people using melatonin incorrectly, as if it were a sleeping pill, when it’s actually a circadian regulator. Your circadian rhythm, or your body’s internal clock, essentially regulates energy levels throughout the day through a variety of actions, including signaling that it’s time to go to bed.
“So no one needs it if they have a problem falling asleep unless it’s due to a circadian misalignment like flying to a new time zone or starting to work the night shift,” Breus tells mbg.