Melatonin is a manmade form of a hormone produced in the brain that helps regulate your sleep and wake cycle.
Melatonin has been used in alternative medicine as a likely effective aid in treating insomnia (trouble falling asleep or staying asleep). It is also likely effective in treating sleep disorders in people who are blind.
Melatonin is also possibly effective in treating jet lag, high blood pressure, tumors, low blood platelets (blood cells that help your blood to clot), insomnia caused by withdrawal from drug addiction, or anxiety caused by surgery. A topical form of melatonin applied to the skin is possibly effective in preventing sunburn.
Melatonin has also been used to treat infertility, to improve sleep problems caused by shift work, or to enhance athletic performance. However, research has shown that it may not be effective in treating these conditions.
Other uses not proven with research have included treating depression, bipolar disorder, dementia, macular degeneration, attention deficit hyperactivity disorder, enlarged prostate, chronic fatigue syndrome, fibromyalgia, restless leg syndrome, stomach ulcers, irritable bowel syndrome, nicotine withdrawal, and many other conditions.
It is not certain whether melatonin is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA.
Melatonin is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.