General Information

Melatonin or 5-methoxy-N-acetyltryptamine is a neurohormone used to regulate sleep-wake cycles in patients with sleep disorders. Endogenous melatonin is secreted by the pineal gland in all animals exhibiting circadian or circannual rhythms. Melatonin plays a proven role in maintaining sleep-wake rhythms, and supplementation may help to regulate sleep disturbances that occur with insomnia, jet lag, rotating shift-work, depression, chronic kidney disease, critical care unit stays, and various neurological disabilities. Clinical study of melatonin continues to elucidate the role of melatonin in a variety of neurologic, hormonal, gastrointestinal, and neoplastic disorders The effects of melatonin as a hormone were first noted in 1917, when dark-skinned tadpoles fed a pineal gland extract were noted to develop lighter skin. Melatonin was isolated from the pineal gland in 1958. Commercial melatonin products are primarily synthesized from 5-methoxyindole; rarely, commercial products are derived from animal (bovine) pineal glands. Use of animal based melatonin products is not recommended due to the potential risk of contamination from animal-based infectious prions and viruses, which may cause serious illness. Oral melatonin is included in the Natural Health Products ingredients/monograph database for Health Canada.1 In Europe, melatonin is available by prescription only under the brand name Circadin, which is marketed as monotherapy for the short-term treatment of primary insomnia characterised by poor quality of sleep in patients who are aged 55 or over.(2) The American Sleep Disorder Association considers melatonin an experimental drug and does not recommend its use without medical supervision. Melatonin has been classified as an orphan drug by the U.S. Food and Drug Administration (FDA) since 1993 for circadian rhythm sleep disorders in blind patients who have no light perception, a condition often known as non-24-hour sleep-wake disorder (non-24), a condition that occurs when the blind patient cannot synchronize their circadian rhythms to a light-dark cycle. In 2013, an additional orphan drug designation was granted by the FDA for the use of melatonin for the treatment of neonatal hypoxic ischemic encephalopathy. Melatonin is also available over the counter in the U.S., and products are marketed under the Dietary Supplement and Health Education Act of 1994 (DSHEA).

NOTE: In the US, nutraceuticals are marketed under the Dietary Supplement and Health Education Act of 1994 (DSHEA). Consequently, scientific data supporting claimed benefit(s) are not always available for nutraceuticals as they are for traditional pharmaceuticals since nutraceuticals are not regulated as drugs. Consumers should also note that rigid quality control standards are not required for nutraceuticals and substantial variability can occur in both the potency and the purity of these products.