Melatonin is a hormone naturally released in the evening that promotes sleepiness and facilitates falling asleep.

“Now, melatonin, a lot of people think of it as a supplement, but melatonin is naturally released as the evening comes about and into the nighttime hours. It's the hormone that makes you feel sleepy and allows you to fall asleep.”

“Melatonin induces sleepiness. Melatonin during development is also responsible for timing the secretion of certain hormones that are vitally important”