A hormone that the body produces is melatonin. It controls the cycles of night and day or sleep and wakefulness. Supplemental melatonin is often created in a lab. The body produces more melatonin when it is dark, which instructs the brain to go to sleep. Melatonin synthesis is reduced and the body is awakened by light. Melatonin levels can be low in those who struggle to fall asleep. Melatonin supplementation is believed to aid in improving their ability to fall asleep.
Melatonin is a key player in the control of sleep and waking cycles in animals. Melatonin levels in newborn humans are typically normal around three months after birth, with the maximum levels being found between midnight and eight in the morning. Human melatonin production decreases with age. Additionally, when children grow into adults, the melatonin release cycle is delayed, resulting in later sleeping and waking hours.