Patients with sleep disorders can employ the neurohormone melatonin, also known as 5-methoxy-N-acetyltryptamine, to control their sleep-wake cycles. All species that display circadian or circannual rhythms have endogenous melatonin released by the pineal gland. The maintenance of sleep-wake rhythms is a known function of melatonin, and supplementation may assist to manage sleep abnormalities brought on by insomnia, jet lag, rotating shift work, depression, chronic renal disease, hospitalizations in intensive care units, and different neurological conditions. The function of melatonin in a number of neurologic, hormonal, gastrointestinal, and neoplastic illnesses is still being clarified by clinical research. When dark-skinned tadpoles fed a pineal gland extract were observed to have lighter skin, the effects of melatonin as a hormone were first discovered in 1917. In 1958, melatonin was extracted from the pineal gland. The majority of commercial melatonin products are made from 5-methoxyindole; occasionally, goods are made from animal (bovine) pineal glands. Due to the potential risk of contamination from infectious prions and viruses derived from animals, which may result in serious sickness, it is not advised to use melatonin products derived from animals. The Natural Health Products ingredients/monograph database for Health Canada lists oral melatonin. 1 Melatonin is only available by prescription in Europe under the brand name Circadin, which is promoted as a monotherapy for the short-term management of primary insomnia in patients 55 years of age or older and characterized by poor sleep quality. 2 Melatonin is regarded as an experimental medicine by the American Sleep Disorder Association, who do not advise using it unsupervised. Since 1993, the U.S. Food and Drug Administration (FDA) has designated melatonin as an orphan drug to treat non-24-hour sleep-wake disorder (non-24), a condition that develops when blind patients are unable to synchronize their circadian rhythms to a light-dark cycle and results in circadian rhythm sleep disorders. For the purpose of treating neonatal hypoxia ischemic encephalopathy, the FDA added melatonin to its list of orphan drugs in 2013. In the United States, melatonin is also offered as an over-the-counter drug in accordance with the Dietary Supplement and Health Education Act of 1994. (DSHEA).

NOTE: The Dietary Supplement and Health Education Act of 1994 governs the marketing of nutraceuticals in the United States (DSHEA). Since nutraceuticals are not regulated like drugs, scientific evidence to support any claimed benefit(s) may not always be available as it is for conventional pharmaceuticals. Additionally, consumers should be aware that the potency and purity of nutraceuticals can vary significantly, and strict quality control standards are not necessary for these products.