Melatonin

is a type of hormone secreted in the pineal gland, a small gland in the brain. It controls the sleep-wake cycle and the internal clock (biological rhythm). Apart from helping you fall asleep, melatonin has many other benefits. In early childhood, melatonin levels are quite high, so babies sleep a lot, after which melatonin synthesis begins to decline. By the age of 40, relatively enough melatonin is produced. Then, due to stress, irregular and unhealthy eating, falling asleep very late at night and a number of other reasons, this synthesis decreases. This is one of the reasons why older people do not sleep well.