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Printed from https://bottledhope.co/supplements/melatonin/. Last reviewed 2026-10-12. Check the site for the latest version.

Melatonin

A hormone the brain makes in response to darkness, also made synthetically and sold in the US as a supplement that adults and children take as a sleep aid.

Explained simply · Last reviewed

What it is

Melatonin is a hormone that the brain produces in response to darkness, according to NCCIH, the US agency that studies complementary medicine. NCCIH says it helps with the timing of the body's circadian rhythms, its 24-hour internal clock, and with sleep, and that being exposed to light at night can block its production. It says melatonin supplements can be made from animals or microorganisms, but most often they are made synthetically.

More about Melatonin

NCCIH says it helps with the timing of the body's circadian rhythms, its 24-hour internal clock, and with sleep, and that being exposed to light at night can block its production. It says melatonin supplements can be made from animals or microorganisms, but most often they are made synthetically.

A 2022 report in CDC's MMWR describes melatonin as a widely available over-the-counter sleep aid for adults and children. It says melatonin is used for insomnia in adults and for primary sleep disorders in children. A 2024 report by CDC authors in MMWR says the share of US adults using melatonin rose from 0.4% in 1999–2000 to 2.1% in 2017–2018.

How melatonin is sold differs by country, according to NCCIH's fact sheet last updated in May 2024. In the United States it is considered a dietary supplement, which means the FDA regulates it less strictly than a prescription or over-the-counter drug. In several other countries, NCCIH adds, melatonin is available only with a prescription and is considered a drug.

At a glance

Safety: known risks, 5 groups who should avoid it or take extra care and 1 documented interaction. See Safety ↓

Claims made about Melatonin, and how strong the evidence is for each:

Each rating follows our published rules and the sources cited for it. We don’t add our own medical judgment. How we rate

Safety

Read this before the ratings below.

Risks

  • The cited health authority says that short-term use of melatonin supplements appears to be safe for most people, but that information on long-term safety is lacking, and that there is not yet enough information about possible side effects, particularly at doses higher than what the body normally produces, to have a clear picture of overall safety.
  • Side effects reported in short-term studies in adults, surgical patients and critically ill patients were mild, according to a 2015 review the authority describes. They included headache, dizziness, nausea and sleepiness.
  • Daytime drowsiness and sleepiness. The authority says melatonin may stay active in older people longer than in younger people and cause daytime drowsiness. The 2002 Cochrane jet lag review reports that hypnotic effects after melatonin occurred in five of its trials, affecting about 10% of participants, and that melatonin taken at the wrong time, early in the day, is liable to cause sleepiness.
  • Allergic reactions. The authority says there may be a risk of allergic reactions. The 2002 Cochrane review describes reports of fixed drug eruption, which it calls an allergic manifestation, as appearing convincing.
  • Difficulty swallowing and breathing. The 2002 Cochrane review reports one trial participant who had difficulty swallowing and breathing within 20 minutes of a first dose; the symptoms subsided after 45 minutes and came back, somewhat milder, when they took another dose.
  • A 2015 American Academy of Sleep Medicine guideline reports that headaches, sleepiness, low and high blood pressure, stomach upset and worsening of the hair-loss condition alopecia areata have been reported at higher doses in healthy adults, and at lower doses in people with relevant pre-existing conditions. It also notes that melatonin has been associated with an increase in depressive symptoms, and that one study found impaired glucose tolerance in healthy women after melatonin.
  • What the trial reviews found. The 2014 Cochrane shift-work review found that side effects did not differ between melatonin and placebo, except for vivid dreams or nightmares during daytime sleep in three people taking melatonin. The 2020 Cochrane dementia review found no serious adverse effects reported, and low-certainty evidence from one trial of 151 people that the melatonin and placebo groups did not differ in adverse event reports. The 2017 insomnia guideline could not pool harms data and reports that none of its trials found clinically significant differences in adverse events. A 2022 meta-analysis found no significant difference in dropouts because of side effects, the most frequent being headaches and migraines, and its authors say this should be taken cautiously because few trials collected tolerability data. The 2002 Cochrane review says the adverse effects of melatonin have not been adequately assessed.
  • Raised liver enzymes in one small trial of a high dose. A 2026 systematic review of melatonin trials in multiple sclerosis reports one trial in people with primary progressive multiple sclerosis also taking the MS medicine ocrelizumab. That trial gave a dose far higher than any other trial in the review used, which the reviewers call "high-dose pharmacological administration". Liver enzymes rose (hypertransaminasemia) in three of the four people given melatonin and none of four given placebo, and the high-dose phase was stopped. The abnormalities improved after melatonin was stopped and came back in one person when it was restarted. All three affected participants were women taking several medicines that share liver pathways with melatonin.
  • How far that finding reaches. The 2026 multiple sclerosis review rates the liver evidence very low certainty, citing "only four exposed participants". It says "The randomized comparison, temporal relationship, dechallenge, and rechallenge strengthen causal concern". It says the findings "cannot be generalized beyond this small, highly selected, polymedicated population, but they rule out calling melatonin uniformly safe across its full dose range", and that they "do not generalize directly to conventional doses, but they carry clinical relevance when considering high-dose preparations, compounded formulations, or patients receiving multiple hepatically metabolized medications". At conventional doses it found no consistent pattern of serious toxicity (low certainty), but notes incomplete adverse-event reporting and trials too small to exclude uncommon harms.
  • In children, the authority says reported side effects have usually been mild, including drowsiness, increased bedwetting or urination in the evening, headache, dizziness and agitation. It says there is little information on the long-term effects of melatonin use in children, and that because melatonin is a hormone it is possible that supplements could affect hormonal development, including puberty, menstrual cycles and overproduction of the hormone prolactin, "but we don’t know for sure".
  • Products may not contain what the label says. The authority reports that a 2017 study of 31 melatonin supplements found that for most, the amount of melatonin did not match the label, and 26 percent contained serotonin, a hormone that can have harmful effects even at relatively low levels. It also reports that a 2023 study found 22 of 25 melatonin gummy products were inaccurately labeled: one had no detectable melatonin, and the rest ranged from 74 to 347 percent of the labeled quantity. The 2002 Cochrane and 2014 BMJ Clinical Evidence reviews call for routine pharmaceutical quality control of melatonin products.
  • Accidental ingestion by young children. A 2022 report in CDC's MMWR found that reports to US poison control centers of melatonin ingestion by people aged 19 and under rose 530% from 2012 to 2021, driven largely by unintentional ingestions by children aged 5 and under. Most children had no symptoms. Hospitalizations and more serious outcomes also increased; most hospitalized patients were teenagers who had taken melatonin intentionally. Over the ten years, 287 needed intensive care, five needed mechanical ventilation and two children under 2 died, although the report says the data could not confirm whether the deaths were caused by melatonin alone. A 2024 report by CDC authors in MMWR estimated about 11,000 emergency department visits for unsupervised melatonin ingestion by children aged 5 and under from 2019 to 2022, and says many involved flavored products such as gummies.

Who should avoid it or take extra care

  • People with epilepsy: the cited authority says they need to be under medical supervision when taking melatonin. The 2002 Cochrane review says case reports suggest people with epilepsy may come to harm from melatonin, and the 2015 AASM guideline advises caution.
  • Pregnancy and breastfeeding: the authority reports a lack of research on the safety of melatonin in pregnant or breastfeeding women.
  • Older people with dementia: the 2015 AASM guideline suggests that clinicians avoid melatonin as a treatment for irregular sleep-wake rhythm disorder in older people with dementia (see the rating below).
  • Children: the authority advises parents to speak with a health care provider before giving a child melatonin, and to store it safely. The 2024 MMWR report by CDC authors highlights the importance of keeping all medications and supplements, including gummies, out of children's reach and sight.
  • Anyone taking medicine: the authority advises consulting a health care provider before using melatonin.

Documented interactions

  • Blood thinners (for example warfarin): The cited authority says people taking blood thinner medications need to be under medical supervision when taking melatonin. The 2002 Cochrane review lists case reports of bleeding and of changes in blood-clotting tests, each a suspected interaction with warfarin, and says an interaction with warfarin "may threaten life" and needs study. The 2014 BMJ Clinical Evidence review says people taking an oral anticoagulant should not use melatonin without medical supervision, and the 2015 AASM guideline advises caution in people taking warfarin. Source [1]Source [2]Source [3]Source [4]

Safety sources: Source [1]Source [2]Source [3]Source [4]Source [5]Source [6]Source [7]Source [8]Source [9]Source [10]Source [11]Source [12]

What the evidence says

Each claim is rated on its own evidence. Ratings follow the scale on our methodology page.

  • Improves sleep in adults with chronic insomnia Evidence rating: Limited

    Adults with long-term insomnia take it hoping to fall asleep faster and stay asleep.

    A 2017 sleep medicine guideline rated the evidence from three trials low to very low quality and suggested clinicians not use melatonin; a 2022 review found no significant difference from placebo.

    A 2017 guideline from the American Academy of Sleep Medicine (AASM) found three trials it could analyze. All were in adults over 55 taking a prolonged-release form for three weeks. The panel rated the evidence very low quality for sleep quality, total sleep time, time awake after falling asleep and number of awakenings. It rated time taken to fall asleep low quality, and there the one trial's reduction fell below the level the panel counted as clinically significant.

    The panel described the minimal evidence as "weakly against melatonin's efficacy". It suggested that clinicians not use melatonin for sleep onset or sleep maintenance insomnia (a weak recommendation). Its summary for melatonin found "weak evidence against clinically significant efficacy in the treatment of sleep onset insomnia". But it adds that "mixed evidence suggests possible improvement" in sleep latency, the time taken to fall asleep, in an elderly population. It also states that a recommendation against use based on low-quality evidence "is not equivalent to a demonstration of ineffectiveness".

    A 2022 meta-analysis found no statistically significant difference from placebo on any sleep measure it could pool in adults with insomnia. Two trials were behind each measure. NCCIH, the US agency that studies complementary medicine, reports on guidelines from the AASM (2017) and the American College of Physicians (2016). It says they found not enough strong evidence on the effectiveness or safety of melatonin for chronic insomnia to recommend its use.

    Sources: Source [1]Source [2]Source [3]

  • Prevents or reduces jet lag Evidence rating: Limited

    Travellers crossing several time zones take it hoping to avoid jet lag.

    A Cochrane review found less jet lag with melatonin in eight of ten trials but did not grade its evidence; a 2014 review drawing on it rated the evidence low quality.

    A Cochrane review of ten trials, whose searches were last updated in 2008, looked at flights crossing five or more time zones. In eight of the trials, melatonin taken close to the target bedtime at the destination reduced jet lag. The review concluded that melatonin is "remarkably effective in preventing or reducing jet lag". It did not grade how sure it could be of its evidence (certainty). It notes that most trials were described too briefly, and that most did not state which form of melatonin they used.

    A 2014 BMJ Clinical Evidence review, drawing on that Cochrane review, rated the evidence low quality. It found melatonin may be more effective than placebo at reducing jet lag scores after eastward and westward flights. It also found melatonin may improve sleep quality after eastward flights. It downgraded the jet lag evidence because formulations were not standardized and regimens varied.

    NCCIH says research suggests melatonin supplements may help with jet lag. The two reviews differ on how strong the evidence is, and this page takes the lower rating.

    Sources: Source [1]Source [2]Source [3]

  • Helps shift workers sleep after a night shift Evidence rating: Limited

    People who work night shifts take it hoping to sleep longer during the day.

    A 2014 Cochrane review found low-quality evidence that melatonin may lengthen sleep after a night shift by about 24 minutes, but not other measures of sleep quality.

    A 2014 Cochrane review studied shift workers, who may or may not have had sleep problems. It found low-quality evidence that melatonin taken after a night shift may lengthen daytime sleep compared with placebo. The difference was about 24 minutes (seven trials, 263 people). For night-time sleep, it was about 17 minutes (three trials, 234 people).

    When the reviewers left out the two trials they judged at high risk of bias, the effect on sleep length after the night shift was no longer statistically significant. For time taken to fall asleep, they say melatonin "may lead to similar sleep latency times as placebo" (low quality). The review's abstract and its summary table give different figures for this estimate. Sleepiness during the night shift was measured in one small trial only.

    The reviewers concluded that there is "low quality evidence that melatonin improves sleep length after a night shift but not other sleep quality parameters". NCCIH describes the studies on whether melatonin helps shift workers as generally small or inconclusive.

    Sources: Source [1]Source [2]

  • Improves sleep in people with moderate-to-severe Alzheimer's disease dementia and sleep problems Evidence rating: Evidence against

    People caring for someone with Alzheimer's disease give it hoping it will help that person sleep.

    A 2020 Cochrane review found low-certainty evidence that melatonin may have little or no effect on any major sleep outcome in moderate-to-severe Alzheimer's disease dementia with sleep problems.

    A 2020 Cochrane review of drug treatments for sleep problems in dementia concludes that "The studies reviewed suggest that melatonin is unlikely to be of benefit to people with moderate‐to‐severe dementia due to Alzheimer's disease (AD) and sleep problems." It found five melatonin trials. Only two, in 184 people, gave data on its main sleep outcomes that could be pooled. Most participants had moderate-to-severe dementia due to Alzheimer's disease.

    The review found low-certainty evidence that melatonin, at the doses tested, may have little or no effect on any major sleep outcome over eight to ten weeks. That includes total night-time sleep. The review rates most outcomes low certainty because of imprecision. In its results, it rates carer-rated sleep quality moderate certainty ("probably has little or no effect"). Its discussion, though, says the melatonin evidence was rated low certainty for all outcomes. Its counts of participants in the melatonin trials also differ between sections.

    A 2015 AASM guideline makes a recommendation limited to older people with dementia who have irregular sleep-wake rhythm disorder. It suggests that clinicians avoid melatonin as a treatment for that disorder in this group (a weak recommendation, low-quality evidence). It bases this on one trial that did not show a benefit for total sleep time, and on evidence from another study that melatonin could be harmful in this group. It concludes that "the potential for harms outweighs the possibility for benefits".

    Sources: Source [1]Source [2]

  • Improves sleep in children with autism Evidence rating: Limited

    Parents of children with autism give it hoping their child will fall asleep sooner and sleep longer.

    Two overlapping reviews found children with autism fell asleep sooner and slept longer with melatonin; neither graded its certainty, and they disagree on night awakenings.

    Two meta-analyses that share trials found benefit on some sleep measures. Neither graded the certainty of its evidence. A 2023 meta-analysis pooled four placebo-controlled trials in 238 children with autism, lasting 4 to 13 weeks. It found that melatonin shortened the time taken to fall asleep, lengthened total sleep and reduced night awakenings. It found that the trials' results differed a lot from each other (high heterogeneity). Its authors say the small number of studies may have reduced the accuracy of the results, and that more and larger studies are needed.

    A 2022 meta-analysis analyzed trials in which every child had both autism and insomnia separately from its other autism trials. It found shorter time to fall asleep and longer total sleep in both groups. But it found no statistically significant change in night awakenings, so the two reviews disagree on awakenings. All four trials in the 2023 meta-analysis are among the autism trials in the 2022 one. So the two are not independent confirmations.

    NCCIH reports that in a 2019 review, children with autism fell asleep 37 minutes earlier and slept 48 minutes longer with melatonin in the short term. It says there is a lot that is not known about melatonin use in children, including its effects over long periods.

    Sources: Source [1]Source [2]Source [3]

  • Helps children with ADHD and insomnia fall asleep Evidence rating: Limited

    Parents of children with ADHD and insomnia give it hoping their child will fall asleep sooner.

    A 2022 review pooled two trials in children and adolescents with ADHD and insomnia and found they fell asleep about 18 minutes sooner on average; it did not grade its certainty.

    A 2022 meta-analysis could pool only two trials, in 124 children and adolescents who all had both ADHD and insomnia. It could pool them for one measure only. Melatonin shortened the time taken to fall asleep by about 18 minutes on average compared with placebo. That was measured with a wrist-worn activity monitor. The review did not grade the certainty of this evidence.

    NCCIH reports that in a 2019 review, children with ADHD fell asleep 20 minutes earlier and slept 33 minutes longer with melatonin in the short term. It adds that most of the review's studies were small, and all were relatively brief.

    Sources: Source [1]Source [2]

  • Helps children with insomnia fall asleep and sleep longer Evidence rating: Limited

    Parents of children with insomnia give it hoping their child will fall asleep sooner and sleep longer.

    A 2022 review found children with insomnia fell asleep about 23 minutes sooner and slept about 32 minutes longer than on placebo; it did not grade its certainty.

    A 2022 meta-analysis analyzed children with insomnia as a separate group from children with neurodevelopmental conditions. Compared with placebo, melatonin shortened the time taken to fall asleep by about 23 minutes (four trials, 221 children). It lengthened total sleep by about 32 minutes (four trials, 168 children). Both were measured by sleep diary. The review did not grade the certainty of this evidence. It rated most trials in children as having "some concern" for risk of bias.

    NCCIH reports that in a 2019 review, children with chronic sleep-onset insomnia fell asleep 24 minutes earlier and slept 25 minutes longer with melatonin in the short term. It says there are uncertainties about the effects of long-term use, and about whether the benefits outweigh the possible risks.

    Sources: Source [1]Source [2]

How and when to take it

What the cited sources say about taking it. Ask your doctor or pharmacist what applies to you.

  • For jet lag, reviewers found the timing matters

    The 2002 Cochrane review says that "The timing of the melatonin dose is important", and that if it is taken at the wrong time, early in the day, "it is liable to cause sleepiness and delay adaptation to local time". In the trials it reviewed that found less jet lag, melatonin was taken close to the target bedtime at the destination. Source [1]

  • Store it out of children's reach and sight

    A 2024 report by CDC authors in MMWR found that most emergency department visits for unsupervised melatonin ingestion by young children involved solid products, most often gummies where the form was recorded, and notes that in the United States melatonin products do not require child-resistant packaging. It says that selecting products with child-resistant packaging "might be advisable in homes with young children". Source [1]

Which form the evidence used

Supplements are sold in several forms. This is what the sources on this page say about them — which form the research used, and any comparison those sources themselves made. Where they made none, this page does not rank the forms.

  • Fast-release (immediate-release) melatonin, What the sources supportDetails

    Most trials in the 2002 Cochrane jet lag review did not state which form they used. In the one trial it describes that compared forms, a slow-release tablet was less effective for jet lag than fast-release tablets, which the reviewers say suggests that a brief, higher peak of melatonin in the blood works better. The 2020 Cochrane dementia review reports that its forest plots did not suggest any difference between immediate-release and slow-release forms. A 2022 meta-analysis could not compare the forms, because most studies used inconsistent formulations. Source [1]Source [2]Source [3]

  • Prolonged-release (slow-release) melatonin, What the sources supportDetails

    The three trials the 2017 American Academy of Sleep Medicine insomnia guideline could analyze all gave a prolonged-release form to adults over 55. The authors of the 2022 meta-analysis write that "solid empirical evidence suggesting that the prolonged-release melatonin is superior to immediate-release melatonin is lacking", a conclusion they quote from a 2017 expert commentary and say "appears still true", while adding that prolonged-release melatonin "might improve sleep continuity". The same review also says "we could not find any evidence that melatonin improves night awakenings". See the note above for what the reviews found when forms were compared. Source [1]Source [2]

Sources

  1. Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline
    Journal of Clinical Sleep Medicine, 2017 · Systematic review · Primary source · Certainty: very low
    Some of its authors disclose ties to industry.
  2. Efficacy on sleep parameters and tolerability of melatonin in individuals with sleep or mental disorders: A systematic review and meta-analysis
    Neuroscience and Biobehavioral Reviews, 2022 · Meta-analysis · Primary source
  3. Melatonin: What You Need To Know
    National Center for Complementary and Integrative Health, NIH, 2024 · Health authority summary · Primary source
  4. Melatonin for the prevention and treatment of jet lag
    Cochrane Database of Systematic Reviews, 2002 · Systematic review · Primary source
  5. Jet lag
    BMJ Clinical Evidence, 2014 · Systematic review · Primary source · Certainty: low
  6. Pharmacological interventions for sleepiness and sleep disturbances caused by shift work
    Cochrane Database of Systematic Reviews, 2014 · Systematic review · Primary source · Certainty: low
  7. Pharmacotherapies for sleep disturbances in dementia
    Cochrane Database of Systematic Reviews, 2020 · Systematic review · Primary source · Certainty: low
  8. Clinical Practice Guideline for the Treatment of Intrinsic Circadian Rhythm Sleep-Wake Disorders: Advanced Sleep-Wake Phase Disorder (ASWPD), Delayed Sleep-Wake Phase Disorder (DSWPD), Non-24-Hour Sleep-Wake Rhythm Disorder (N24SWD), and Irregular Sleep-Wake Rhythm Disorder (ISWRD). An Update for 2015: An American Academy of Sleep Medicine Clinical Practice Guideline
    Journal of Clinical Sleep Medicine, 2015 · Systematic review · Primary source · Certainty: low
  9. Efficacy of Melatonin for Insomnia in Children with Autism Spectrum Disorder: A Meta-analysis
    Neuropediatrics, 2023 · Meta-analysis · Primary source
  10. Pediatric Melatonin Ingestions — United States, 2012–2021
    MMWR. Morbidity and Mortality Weekly Report (CDC), 2022 · Observational study · Supporting source
  11. Erratum: Vol. 71, No. 22: Pediatric Melatonin Ingestions — United States, 2012–2021
    MMWR. Morbidity and Mortality Weekly Report (CDC), 2022 · Observational study · Supporting source
  12. Notes from the Field: Emergency Department Visits for Unsupervised Pediatric Melatonin Ingestion — United States, 2019–2022
    MMWR. Morbidity and Mortality Weekly Report (CDC), 2024 · Observational study · Supporting source
  13. Melatonin supplementation in multiple sclerosis: a systematic review of clinical, imaging, biomarker, and safety outcomes
    Frontiers in Neurology, 2026 · Systematic review · Primary source · Certainty: very low

Page history

Show all 6 changes to this page
  • — Safety section adds a 2026 systematic review's report of raised liver enzymes in three of four people given a high dose of melatonin in one small trial in multiple sclerosis, with the review's own limits on that finding. No rating changed.
  • — Rewritten to the content style guideline; ratings and sources unchanged.
  • — Published. All seven claims, the safety section and every source passed the site's source and wording reviews over two revision rounds. Pediatric and review-access gaps stay logged in docs/08-open-decisions.md.
  • — Revised after the second review. The adult insomnia summary now reports the 2017 guideline's note of possible improvement in time taken to fall asleep in older people; the prolonged-release note adds the 2022 meta-analysis finding on night awakenings; the jet lag timing advice and the packaging note are attributed more closely to their sources. No rating changed.
  • — Revised after source review. The dementia claim now covers moderate-to-severe Alzheimer's disease dementia with sleep problems, the group the Cochrane review concludes melatonin is unlikely to benefit, and quotes that conclusion. Safety wording now uses each source's own terms, and the CDC reports are attributed to their authors. No rating changed.
  • — First draft. Sleep in Alzheimer's disease dementia rated evidence against; adult chronic insomnia, jet lag, sleep after night shifts, and sleep in children with autism, with ADHD and insomnia, or with insomnia rated limited.