Abstract
Melatonin is synthesized in the pineal gland of the brain from the amino acid tryptophan. Light cycles regulate melatonin synthesis and release, which is responsible for the circadian and seasonal signal within the human brain. Suprachiasmatic nuclei, located above the optic chiasma, expresses a series of genes that reacts via light input. Secretion of melatonin lowers body temperature, regulates immune function, reproductive functions, and has antioxidant properties.
