Melatonin is a hormone synthesized and secreted by the pineal gland each night that affects the body's circadia rhythm (sleep pattern).

The pineal gland functions as the timekeeper of the brain, helping manage the sleep-wake cycle. Melatonin production in the body is triggered by darkness and inhibited by light, helping the body manage its natural sleep rhythm.

Discovered in the 1950s as a neurohormone (N-acetyl-5 methoxytryptamine) produced in the brain by the pineal gland from the amino acid tryptophan, melatonin bulk powder became available as a dietary supplement in 1994.The precursor of melatonin, tryptophan (L-tryptophan), is an essential amino acid synthesized from proteins during digestion via the action of proteolytic enzymes. During the day. it is converted to serotonin (a brain chemical involved with mood) before being converted to melatonin.

Melatonin bulk powder has also been demonstrated to have powerful antioxidant properties, protecting cells from damage caused by free radical molecules.