Melatonin: What You Need To Know
On this page:
- What’s the Bottom Line?
- What Is Melatonin?
- What the Science Says About Safety and Side Effects
- What the Science Says About Melatonin
- If You Are Considering Using Melatonin
- For More Information
- Key References
What’s the Bottom Line?
How much do we know about melatonin supplements?
- Researchers have conducted many studies on whether melatonin supplements may help people with various sleep disorders; however, important questions remain about its usefulness, how much to take and when to take it, and long-term safety.
What do we know about the usefulness of melatonin supplements?
- Melatonin supplements may help some people with certain sleep disorders, including jet lag, sleep problems related to shift work, and delayed sleep phase disorder (one in which people go to bed but can’t fall asleep until hours later), and insomnia.
What do we know about the safety of melatonin supplements?
- Melatonin supplements appear to be safe when used short-term; less is known about long-term safety.
What Is Melatonin?
Melatonin is a natural hormone that plays a role in sleep. Melatonin production and release in the brain is related to time of day, rising in the evening and falling in the morning. Light at night blocks its production. Melatonin dietary supplements have been studied for sleep disorders, such as jet lag, disruptions of the body’s internal “clock,” insomnia, and problems with sleep among people who work night shifts. It has also been studied for dementia symptoms.
For more information about sleep, visit the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institute of Neurological Diseases and Stroke.
What the Science Says About Safety and Side Effects
Melatonin appears to be safe when used short-term, but the lack of long-term studies means we don’t know if it’s safe for extended use.
- In one study, researchers noted that melatonin supplements may worsen mood in people with dementia.
- In 2011, the U.S Food and Drug Administration issued a warning to a company that makes and sells “relaxation brownies,” stating that the melatonin in them has not been deemed a safe food additive.
- Side effects of melatonin are uncommon but can include drowsiness, headache, dizziness, or nausea. There have been no reports of significant side effects of melatonin in children.
What the Science Says About Melatonin
This section highlights results of research on melatonin for some specific sleep disturbances.
For Sleep Disorders
Studies suggest that melatonin may help with certain sleep disorders, such as jet lag, delayed sleep phase disorder (a disruption of the body’s biological clock in which a person’s sleep-wake timing cycle is delayed by 3 to 6 hours), sleep problems related to shift work, and some sleep disorders in children. It also has been shown to be helpful for a sleep disorder that causes changes in blind peoples’ sleep and wake times. Study results are mixed on whether melatonin is effective for insomnia in adults, but analyses of some studies suggest it may slightly reduce the time it takes to fall asleep.
Jet lag is caused by rapid travel across several time zones; its symptoms include disturbed sleep, daytime fatigue, indigestion, and a general feeling of discomfort.
- In a 2009 systematic review, results from six small studies and two large studies suggested that melatonin may ease jet lag.
- In a 2007 clinical practice guideline, the American Academy of Sleep Medicine supported using melatonin to reduce jet lag symptoms and improve sleep after traveling across more than one time zone.
Delayed Sleep Phase Disorder
Adults and teens with this sleep disorder have trouble falling asleep before 2 a.m. and have trouble waking up in the morning.
- In a 2007 review of the literature, researchers suggested that a combination of melatonin supplements, a behavioral approach to delay sleep and wake times until the desired sleep time is achieved, and reduced evening light may even out sleep cycles in people with this sleep disorder.
- In a 2007 clinical practice guideline, the American Academy of Sleep Medicine recommended timed melatonin supplementation for this sleep disorder.
Shift Work Disorder
Shift work refers to job-related duties conducted outside of morning to evening working hours. About 2 million Americans who work afternoon to nighttime or nighttime to early morning hours are affected by shift work disorder.
- A 2007 clinical practice guideline and 2010 review of the evidence concluded that melatonin may improve daytime sleep quality and duration, but not nighttime alertness, in people with shift work disorder.
- The American Academy of Sleep Medicine recommended taking melatonin prior to daytime sleep for night shift workers with shift work disorder to enhance daytime sleep.
Insomnia is a general term for a group of problems characterized by an inability to fall asleep and stay asleep.
- In adults. A 2013 meta-analysis of 19 randomized placebo-controlled trials included 1,683 people with primary sleep disorders found that melatonin slightly improved time to fall asleep, total sleep time, and overall sleep quality. In a 2007 study of 170 participants with insomnia, aged 55 years or older, researchers found that prolonged-release melatonin significantly improved quality of sleep and morning alertness.
- In children. There’s limited evidence from rigorous clinical trials on melatonin for sleep disorders among young people. A 2011 literature review suggested a benefit with minimal side effects in healthy children as well as youth with attention-deficit hyperactivity disorder, autism, and several other populations. There is insufficient data to make conclusions about the safety and effectiveness of long-term melatonin use.
For other conditions
While there has not been enough research to support melatonin’s use for other conditions:
- Researchers are investigating whether adding melatonin to standard cancer care can improve response rates, survival time, and quality of life.
- Results from a few small clinical studies have led investigators to propose additional research on whether melatonin may help to improve mild cognitive impairment in patients with Alzheimer’s disease (AD) and prevent cell damage associated with amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig’s disease). An analysis of the research suggested that adding sustained-release melatonin (but not fast-release melatonin) to high-blood pressure management reduced elevated nighttime blood pressure.
Improving Sleep Habits in Children
Sleep problems are one of the most common problems parents encounter with their children. There are some simple steps parents can take to improve their children’s sleep, such as having a set bedtime and bedtime routine, avoiding foods or drinks with caffeine, and limiting the amount of screen time. The National Heart, Lung, and Blood Institute has some additional resources for improving sleep habits in both children and adults.
If You Are Considering Using Melatonin
- If you or a family member has trouble sleeping, see your health care provider.
- When you take a melatonin supplement is important because it may affect your biological clock.
- The U.S. Food and Drug Administration regulates dietary supplements such as melatonin, but the regulations for dietary supplements are different and less strict than those for prescription or over-the-counter drugs.
- Some dietary supplements may interact with medications or pose risks if you have medical problems or are going to have surgery.
- Most dietary supplements have not been tested in pregnant women, nursing mothers, or children. If you’re pregnant or nursing a child, it’s especially important to see your health care provider before taking any medication or supplement, including melatonin.
- To use dietary supplements, such as melatonin safely, read and follow label instructions, and recognize that “natural” does not always mean “safe.” For more information, see Using Dietary Supplements Wisely.
- Tell all your health care providers about any complementary health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure safe and coordinated care. For tips about talking with your providers about complementary approaches, see NCCIH’s Time to Talk campaign.
For More Information
The NCCIH Clearinghouse provides information on NCCIH and complementary and integrative health approaches, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.
A service of the National Library of Medicine (NLM), PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals.
NIH Clinical Research Trials and You
The National Institutes of Health (NIH) has created a Web site, NIH Clinical Research Trials and You, to help people learn about clinical trials, why they matter, and how to participate. The site includes questions and answers about clinical trials, guidance on how to find clinical trials through ClinicalTrials.gov and other resources, and stories about the personal experiences of clinical trial participants. Clinical trials are necessary to find better ways to prevent, diagnose, and treat diseases.
National Heart, Lung, and Blood Institute (NHLBI)
NHLBI supports research and consumer outreach on diseases of the heart, blood vessels, lungs, and blood.
- Barion A, Zee PC. A clinical approach to circadian rhythm sleep disorders. Sleep Medicine. 2007;8(6):566–577.
- Ferguson SA, Rajaratnam SM, Dawson D. Melatonin agonists and insomnia. Expert Review of Neurotherapeutics. 2010;10(2):305–318.
- Gooneratne NS. Complementary and alternative medicine for sleep disturbances in older adults. Clinics in Geriatric Medicine. 2008;24(1):121–138.
- Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database of Systematic Reviews. 2002;(2):CD001520 [edited 2009]. Accessed at www.thecochranelibrary.com on April 10, 2014.
- Jansen SL, Forbes D, Duncan V, et al. Melatonin for the treatment of dementia. Cochrane Database of Systematic Reviews. 2006;(1):CD003802 [edited 2011]. Accessed at www.thecochranelibrary.com on April 10, 2014.
- Morgenthaler T, Lee-Chiong T, Alessi C, et al. Practice parameters for the clinical evaluation and treatment of circadian rhythm sleep disorders: an American Academy of Sleep Medicine report. Sleep. 2007;30(11):1445–1459.
- Sánchez-Barceló EJ, Mediavilla MD, Reiter RJ. Clinical uses of melatonin in pediatrics. International Journal of Pediatrics. 2011;2011:892624.
- van Geijlswijk IM, Korzilius HP, Smits MG. The use of exogenous melatonin in delayed sleep phase disorder: a meta-analysis. Sleep. 2010;33(12):1605–1614.
All Other References
- Arendt JA, Rajaratnam SM. Melatonin and its agonists: an update. British Journal of Psychiatry. 2008;193(4):267–269.
- Arendt J. Shift work: coping with the biological clock. Occupational Medicine. 2010;60(1):10–20.
- Bellapart J, Boots R. Potential use of melatonin in sleep and delirium in the critically ill. British Journal of Anaesthesia. 2012;108(4):572–580.
- Cardinali DP, Furio AM, Brusco LI. Clinical aspects of melatonin intervention in Alzheimer’s disease progression. Current Neuropharmacology. 2010;8(3):218–227.
- Cummings C. Melatonin for the management of sleep disorders in children and adolescents. Paediatrics & Child Health. 2012;17(6):331–333.
- Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013;8(5):e63773.
- Grossman E, Laudon M, Zisapel N. Effect of melatonin on nocturnal blood pressure: meta-analysis of randomized controlled trials. Vascular Health and Risk Management.2011;7:577–584.
- Herxheimer A. Jet lag. Clinical Evidence. 2008;12:2303.
- Lemoine P, Nir T, Laudon M, et al. Prolonged-release melatonin improves sleep quality and morning alertness in insomnia patients aged 55 years and older and has no withdrawal effects. Journal of Sleep Research. 2007;16(4):372–380.
- Lemoine P, Zisapel N. Prolonged-release formulation of melatonin (Circadin) for the treatment of insomnia. Expert Opinion on Pharmacotherapy. 2012;13(6):895–905.
- Morin AK. Strategies for treating chronic insomnia. American Journal of Managed Care. 2006;12(8 Suppl):S230–S245.
- Owens J, Maxim R, McGuinn M. Television-viewing habits and sleep disturbance in school children. Pediatrics. 1999;104(3):e27.
- Reiter RJ, Tan D-X, Manchester LC, et al. Medical implications of melatonin: receptor-mediated and receptor-independent actions. Advances in Medical Sciences. 2007;52:11–28.
- Riemersma-van der Lek RF, Swaab DF, Twisk J, et al. Effect of bright light and melatonin on cognitive and noncognitive function in elderly residents of group care facilities: a randomized controlled trial. JAMA. 2008;299(22):2642–2655.
- Rosenberg R, Doghramji PP. Is shift work making your patient sick? Emerging theories and therapies for treating shift work disorder. Postgraduate Medicine. 2011;123(5):106–115.
- Singh GK, Kenney MK. Rising prevalence and neighborhood, social, and behavioral determinants of sleep problems in US children and adolescents, 2003-2012. Sleep Disorders. 2013;2013:394320.
- Thompson DA, Christakis DA. The association between television viewing and irregular sleep schedules among children less than 3 years of age. Pediatrics. 2005;116(4):851–856.
- Wang X. The anti-apoptotic activity of melatonin in neurodegenerative diseases. CNS Neuroscience & Therapeutics. 2009;15(4):345–357.
- Zee PC, Goldstein CA. Treatment of shift work disorder and jet lag. Current Treatment Options in Neurology. 2010;12(5):396–411.
NCCIH thanks the following people for their technical expertise and review of this publication: Daniel Buysse, M.D., University of Pittsburgh School of Medicine; Nalaka Gooneratne, M.D., M.Sc., Hospital of the University of Pennsylvania; Frank Scheer, Ph.D., Brigham and Women’s Hospital and Harvard Medical School; and D. Lee Alekel, Ph.D., and John (Jack) Killen, Jr., M.D., NCCIH.