Melatonin refers to a hormone made by a brain part called the pineal. Melatonin helps bodies in understanding the time to go to bed and sleep and also the time to wake up. Melatonin is also available in pill form as they are available in natural and synthetic forms. Natural melatonin is manufactured from the pineal glands of the animals and this can get contaminated with virus. This is the reason that it is not recommended. Synthetic melatonin has no risk involved. Melatonin is used in treating insomnia and prevents jet lag. Melatonin promotes health or treats disease has very little scientific evidence. Some people have reported headache, stomach discomfort and depression, however further study is being done. Melatonin is available without the prescription of a doctor in the drug stores and health food stores in the United States. But, as it is not regulated by the government, the safety, purity and effectiveness is far from being guaranteed.