Melatonin as a natural sleep aid is a natural substance that is synthesized from serotonin and produced by the pineal gland. At night, its production is high and naturally signals the body that it is time to sleep. This means that melatonin manages people's awareness and natural reactions to night and day.

People with sleeping problems like insomnia naturally lack these natural substances which cause their bodies to avoid shifting to a restful sleep stage at night. As a sleep aid, those that are obtainable over the counter contain real sleep regulating melatonin.