Melatonin for sleep: what does the evidence show?

A signal for timing, not a universal sleep fix

The body makes melatonin as part of its internal clock, which helps coordinate sleep and wakefulness. Jet lag can happen when travel across time zones puts that clock out of step with local time. Melatonin’s role in the body does not mean that taking extra will solve every cause of poor sleep. Products differ in their form, how they release melatonin and how they are regulated.

See caffeine and sleep, CBD and sleep, and epitalon, melatonin and sleep.23

Jet lag and insomnia need separate evidence

The US National Center for Complementary and Integrative Health says melatonin may help with jet lag and certain sleep–wake timing disorders. For chronic insomnia—ongoing difficulty falling asleep, staying asleep or both—it cites professional guidelines that found insufficient strong evidence to recommend melatonin. It notes cognitive behavioural therapy for insomnia as an initial treatment option.

A study average does not predict whether one person will benefit. Persistent sleep problems deserve assessment rather than an assumption about the body clock. For different products, see ashwagandha, epitalon and 5-HTP and sleep.2

Does melatonin help after a long flight?

A 2021 review combined studies of travellers. On average, people taking melatonin reported fewer jet-lag symptoms after both eastbound and westbound flights. The individual studies did not all agree. In one small double-blind study of 31 people flying from London to eastern Australia, researchers found no significant benefit on several reported symptoms or measures of body-clock adjustment. Neither result predicts one person’s trip.

Timing matters because melatonin can shift the body clock in different directions. The CDC cautions that poorly timed use can put it further out of step. Travel direction, time zones, light, product and health circumstances all matter. Ask a health professional about your journey and product. See travelling with medicines for separate transport and border questions.678

Side effects and interactions

The US National Institutes of Health says short-term use appears safe for most people, but long-term safety is less clear. Melatonin can cause sleepiness. It may remain active longer in older adults and cause daytime drowsiness. Other medicines and health conditions can change the risks. NIH highlights the need for medical supervision for people with epilepsy or taking blood-thinning medicines. Evidence during pregnancy and breastfeeding is limited. Discuss the exact product with a health professional before using it alongside medicines.

Allergic reactions are possible. A 2015 US sleep-medicine guideline gives a weak recommendation against melatonin for irregular sleep–wake rhythm disorder in older people with dementia, based on limited evidence. This concerns a specific sleep disorder and population, not every possible use. Discuss sleep changes and the individual treatment plan with a clinician.12

Children and accidental ingestion

Melatonin may be used for some children’s sleep disorders under appropriate clinical guidance, but it does not replace assessing the cause of the sleep problem. Keep medicines and supplements, including flavoured gummies, out of children’s reach and sight.2

A US CDC analysis estimated about 11,000 emergency visits for unsupervised melatonin ingestions by infants and young children during 2019–2022. This estimates visits, not the risk for every child taking a product as directed. If a child has taken a product unexpectedly, seek prompt advice from a local poison service or urgent medical service.4

NCCIH says there are relatively few studies in children and little information on long-term effects. Because melatonin is a hormone, possible effects on development, including puberty, have been raised, but are not established. Discuss a child’s sleep and any melatonin use with the child’s clinician.2

When is melatonin studied or prescribed for children?

A 2017 trial studied 125 children and adolescents with insomnia and autism or Smith–Magenis syndrome whose sleep had not improved with behavioural measures. They were assigned a particular prolonged-release melatonin product or placebo for 13 weeks. Caregiver diaries suggested roughly 32 minutes more sleep per night with melatonin after adjustment. The product’s developer, Neurim Pharmaceuticals, funded the trial. The group average does not predict a child’s response or establish long-term safety or the effects of other products.

The European Medicines Agency lists Slenyto, a prolonged-release medicine, for insomnia when sleep-hygiene measures have not been enough: for ages 2–18 with autism or specified neurogenetic disorders, and separately for ages 6–17 with ADHD. The exact product information sets out conditions and follow-up; authorisation and availability vary by country. That does not mean every melatonin gummy is suitable or accurately labelled. A paediatric clinician can assess the cause and whether a particular treatment is appropriate.1011

The name on the label is not the whole product

Melatonin is regulated as a dietary supplement in the United States; other countries may regulate it as a medicine. A label states what the manufacturer says is present, but does not independently prove the amount in a particular batch. Forms and release characteristics differ too.

A 2023 laboratory study tested 25 selected US gummies. Twenty-two had measured melatonin more than 10% above or below the label, including one with none detected. Among products containing melatonin, amounts ranged from 74% to 347% of the stated amount—not 347% more.

A separate 2025 FDA-affiliated survey tested 110 selected US supplements marketed for children. Melatonin was detected in 108; amounts ranged from 0% to 667% of the label. An amount equal to 667% of the label is about 6.7 times the stated amount, not 6.7 times more. These selected samples cannot tell us how common discrepancies are across all products, countries or batches. Neither study tested whether a product helps a child sleep.

Ask a pharmacist about the exact product. See how to read a supplement label and medicine interactions. This article does not recommend a dose.259