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 regular cycle of wakefulness and sleep associated with day and night. Small amounts of Melatonin can be found in the foods we eat and it can also be absorbed in the body by taking a supplement.

Studies have 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. Light affects how much melatonin your body produces.

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.

Dosing format

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 breastfeeding should consult a physician before taking any dietary supplements.

Side effects, toxicity, and interactions

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.