(See also Overview of Dietary Supplements.)
Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin is considered a drug and is regulated as such.
Melatonin is used for the short-term regulation of sleep patterns, including jet lag and insomnia. Research into the use of melatonin supplementation for people affected by seasonal affective disorder, regulation of sleep patterns in people who work late shifts, and the resynchronization of the sleep/wake cycle in people with early Alzheimer disease is currently being evaluated.
Some scientific evidence supports use of melatonin to minimize the effects of jet lag, especially in people traveling eastward over 2 to 5 time zones (1-2). However, in one well-designed study, melatonin supplements did not relieve symptoms of jet lag (3), and only a few small studies suggest that these supplements can relieve jet lag symptoms (4-5), indicating that clinical trial results are inconsistent.
Standard dosage is not established and ranges from 0.5 to 5 mg po taken 1 h before usual bedtime on the day of travel and 2 to 4 nights after arrival. Evidence supporting use of melatonin as a sleep aid in adults and children with neuropsychiatric disorders (eg, pervasive developmental disorders) is less strong.
Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev(2):CD001520, 2002.
Buscemi N, Vandermeer B, Pandya R, et al. Melatonin for Treatment of Sleep Disorders. AHRQ Publication No. 05-E002-2, 2004.
Edwards BJ, Atkinson G, Waterhouse J, et al. Use of melatonin in recovery from jet-lag following an eastward flight across 10 time-zones. Ergonomics 43(10):1501-1513, 2000.
Claustrat B, Brun J, David M, et al. Melatonin and jet lag: confirmatory result using a simplified protocol. Biol Psychiatry 3(8):705-711, 1992.
Petrie K, Dawson AG, Thompson L, et al. A double-blind trial of melatonin as a treatment for jet lag in international cabin crew. Biol Psychiatry 33(7):526-530, 1993.