N-acetyl-5-methoxytryptamine, melanocyte-contracting principle, skin-lightening factor
Melatonin is a not a nutrient, but a hormone produced by the pineal gland, a small endocrine gland at the base of the brain. Secretion of melatonin is regulated by exposure to light. Melatonin is believed to play a part in the diurnal cycle, or regular cycle of wakefulness and sleep associated with day and night. Studies have also shown above-average serum levels of melatonin in people with seasonal affective disorder (SAD), a type of depression associated with the short daylight hours in winter.
The pineal gland is the remnant of midline light receptors still present in some lower animals. It is the tie to light that first indicated this function in the pineal gland and later identified the link of melatonin to regulating the day-night wake and sleep cycle. Since that time, melatonin has been studied for its tie to the circadian rhythm and sleep.
Medically Valid Uses:
Taking melatonin can shift the circadian (24-hour) clock approximately one hour, making up for one hour of jet lag. However, studies have shown that jet lag induced by travel through more than two time zones cannot be quickly corrected by melatonin.
Please note that this section reports on claims that have NOT yet been substantiated through scientific studies.
Melatonin is claimed to help alleviate sleep disorders, such as insomnia, and be of benefit in the treatment of depression. There are also claims that melatonin may possibly help improve the function of the immune system, slow the aging process and help manage some cancers when combined with other drugs.
Melatonin is available in both rapid-release and slow-release formulations. The range being studied is 0.5 to 5 mg per day, although a recommended amount has not been established.
Melatonin should be taken two hours or less before regular sleep time.
Women who are pregnant or breast-feeding should consult a physician before taking any dietary supplements.
Side Effects, Toxicity and Interactions:
Melatonin may increase the frequency of seizures in certain types of seizure disorders.
Large doses of melatonin may interfere with ovarian function. Definite interference with sexual development has been demonstrated in animals given supplements of melatonin.
Avoid driving or operating machinery for several hours after taking melatonin. The natural secretion of melatonin is possibly affected by stimulants, including coffee, late night exercise, late night snacks and light in the bedroom.
There are no known significant food or drug interactions.
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Garfinkel D, et al. Improvement of sleep quality in elderly people by controlled-released melatonin. Lancet. 1995;346:541-544.
Haimov I, et al. Sleep disorders and melatonin rhythms in elderly people. BMJ. 1994;309:167.
Lissoni P, Tancini G, Barni S. Treatment of cancer chemotherapy-induced toxicity with the pineal hormone melatonin. Support Care Cancer. 1997;5:126-129.
Waterhouse J, et al. Jet lag. Lancet. 1997;350:1611-1616.