Melatonin is a naturally occurring hormone. In humans, melatonin is produced in several tissues, including the brain (pineal gland), retina, and GI tract. In the brain, melatonin synthesis is stimulated by darkness. Once synthesized, it enters the blood stream and acts as an endocrine hormone involved in sleep regulation and a number of other cyclical physiological functions. Daily biological rhythms thought to be influenced by melatonin include activity and sleep, core body temperature, immune function, antioxidant defenses, blood pressure, feeding, and glucose regulation.
Please note that melatonin supplements are not sleeping pills. Oral melatonin supplements support the human body’s natural circadian rhythms and promote healthy sleep. When taken an hour before bedtime, melatonin supports the natural rise in melatonin that typically occurs before sleep.