Melatonin is a hormone that is secreted by a part of the brain called the pineal gland. The synthesis of melatonin begins with L-tryptophan which is converted into 5?HTP then to serotonin and then to melatonin. Production of melatonin is under the influence of part of the brain known as the hypothalamus. The hypothalamus receives information from the retina of the eye, about the daily patterns of light and dark. The result is the production of physiological and behavioral circadian rhythms. These circadian rhythms help control various functions in the body including the wake/sleep cycle. The amount of melatonin produced varies; synthesis is increased in the dark and decreased in the light. As darkness approaches, melatonin production increases, helping prepare the body for sleep. Studies show that supplemental melatonin may help support a normal sleep cycle, help fight jet-lag and in higher amounts provide antioxidant support.