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The Bottom Line

To date, there are no definite answers about how well melatonin works for a number of conditions or how safe it is when taken for long periods. Hundreds of melatonin studies have been published; many of them involved only small numbers of people, were not scientifically rigorous, and used unspecified types of melatonin products.

The Full Story

Many people know of melatonin as a dietary supplement taken to help with jet lag. Recently, melatonin has made the news as an ingredient in "relaxation" brownies and beverages.

Melatonin is a hormone produced naturally in the human brain. Its primary function is to help us sleep; melatonin production increases at night time. For this reason, people take melatonin supplements for jet lag and sleep disturbances. Research studies for these uses show mixed results – but there is no research showing that melatonin should be added to foods and drinks!

Melatonin supplements may not have consistent amounts of the active ingredient in them. They may be absorbed into the body at different rates. Quality control may be variable. (The U.S. Food and Drug Administration [FDA] is not permitted to regulate dietary supplements in the same way that it monitors prescription and over-the-counter drugs.) This can make it hard to interpret research studies that don't describe the formulation of melatonin used. Melatonin seems to be safe when taken for short periods of time, though there are no studies of long-term safety. Side effects include drowsiness, as expected, but otherwise are about the same as placebo pills (sugar pills). People with seizure disorders should not take melatonin, as there are some reports of seizures occurring in people who took melatonin.

Melatonin for jet lag: Several studies have evaluated the effectiveness of melatonin for jet lag. Most studies were small. Some researchers believe that melatonin is safe and effective when people cross five or more time zones in the eastern direction. Other researchers say that there is no evidence that melatonin helps with sleep problems associated with jet lag, though it may help people to feel more awake during the day. All seem to agree that additional research is needed.

Melatonin for sleep disturbances: A review of more than 125 studies, many of them small, concluded that melatonin doesn't seem to help most people with sleep problems, including people with jet lag and shift workers. There is some evidence that it can help people fall asleep faster. The researchers found that most studies fell short in describing the details of the melatonin used in the study. 

A prescription drug called Ramelteon® acts on the same area of the brain as melatonin. It is prescribed for elderly people with insomnia.

Melatonin for children with ADHD and insomnia: Many children with attention-deficit/hyperactivity disorder (ADHD) have problems falling asleep and staying asleep. A review of four studies of such children found that melatonin often helped them fall asleep faster and sleep longer.

Melatonin in brownies and relaxation drinks: Melatonin was baked into brownies and added to beverages, then marketed as “relaxation” aids. The amount of melatonin was typically more than a usual bedtime dose of 5 milligrams. The FDA required companies to remove melatonin from their products, noting that melatonin has medical uses but is NOT recognized as a safe addition to foods.

Although hundreds of melatonin studies have been published, many of them involved only small numbers of people, were not scientifically rigorous, and used unspecified types of melatonin products. To date, there are no definite answers about how well melatonin works for a number of conditions, and how safe it is when taken for long periods.

If someone may have taken too much melatonin, use the webPOISONCONTROL® online tool for guidance or call Poison Control at 1-800-222-1222. 

Rose Ann Gould Soloway, RN, BSN, MSEd, DABAT emerita
Clinical Toxicologist

For More Information

Melatonin for consumers (Medline)


Bendz LM, Scates AC. Melatonin treatment for insomnia in pediatric patients with attention-deficit/hyperactivity disorder. Ann Pharmacother 2010;44:185-91.

Buscemi N, Vandermeer B, Pandya R, Hooton N, Tjosvold L, Hartling L, Baker G, Vohra S, Klassen T. Melatonin for Treatment of Sleep Disorders. Summary, Evidence Report/Technology Assessment No. 108. (Prepared by the University of Alberta Evidence-based Practice Center, under Contract No. 290-02-0023.) AHRQ Publication No. 05-E002-1. Rockville, MD: Agency for Healthcare Research and Quality. November 2004.

Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database of Systematic Reviews 2002, Issue 2. Art. No.: CD001520. DOI: 10.1002/14651858.CD001520.

Rajaratnam SMW, Cohen Da, Rogers NL. Melatonin and melatonin analogues. Sleep Med Clin. 2009;4:179–193. doi:10.1016/j.jsmc.2009.02.007


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This Really Happened

Case 1: A 2-year-old boy swallowed up to 138 milligrams (mg) of melatonin over an hour. He slept for a couple of hours and was then fine.

Case 2: A 4-year-old girl swallowed an estimated 39 mg of liquid melatonin. She didn't develop drowsiness or any other symptoms.

Case 3: A 50-year-old woman took a deliberate overdose of 100 mg of melatonin time-release tablets. She developed drowsiness that persisted for about 12 hours and her pulse rate was slightly increased for a few hours.