Melatonin is a hormone that plays an important role in the body’s natural wake-sleep cycle. It’s produced by the pineal gland (a small gland in the brain) when it gets dark and signals to the body that it’s time for sleep. Melatonin is sometimes included in sleep remedies. While some sleep remedies contain synthetic (lab-made) melatonin, Sleep Supplement is a natural sleep aid that contains Montmorency cherry - a source of natural melatonin.