Melatonin

Melatonin is a naturally occurring hormone produced by the pineal gland that has numerous biologic effects, including antioxidant properties and potential effects on the sleep-wake cycle and immune system functions. Melatonin is available as a dietary supplement. Long-term effects of supplementation are not known. Melatonin has been studied for its effect on anorexia, depression, fatigue, sleep-wake disturbances, and cognitive impairment in people with cancer.