Melatonin is a hormone made by the pineal gland, a small gland located in the brain. Melatonin helps control your sleep and wake cycles, it inhibits melanin formation and is thought to be concerned with regulating the reproductive cycle. Very small amounts of it are found in foods such as meats, grains, fruits, and vegetables. You can also buy it as a supplement.
A key factor in how human sleep is regulated is exposure to light or to darkness. Exposure to light stimulates a nerve pathway from the retina in the eye to an area in the brain called the hypothalamus. There, a special centre called the suprachiasmatic nucleus (SCN) initiates signals to other parts of the brain that control hormones, body temperature and other functions that play a role in making us feel sleepy or wide awake.
The SCN works like a clock that sets off a regulated pattern of activities that affect the entire body. Once exposed to the first light each day, the clock in the SCN begins performing functions like raising body temperature and releasing stimulating hormones like cortisol. The SCN also delays the release of other hormones like melatonin, which is associated with sleep onset, until many hours later when darkness arrives.
Melatonin Benefits - primary medical use of melatonin is to assist in sleep disorders. Melatonin is involved in many processes, including the regulation of certain immune responses. Melatonin is most famous for regulating the body's internal clock. Melatonin supplements cause very few side effects but they can interact with other drugs.