Melatonin: Clinical Perspectives and Pharmaceutical ApplicationsAbout This Hardback Melatonin is a hormone that is associated with the control of sleep wake cycle and is primarily secreted by the pineal gland at night. It is also taken orally as a dietary supplement to treat short term insomnia such as from shift work or jet lag. Some melatonin receptor agonists are also available as medications that work as melatonin but may have some adverse effects for sleep conditions. Side effects of melatonin use are