Evidence overview
Melatonin
Melatonin is an endogenously-produced hormone that doubles as a widely-used over-the-counter sleep supplement. The research base spans sleep onset, jet lag, shift work, delayed sleep phase, and age-related sleep changes. One of the most-practical questions for consumers is dose: typical supplement doses (1-10 mg) are dramatically higher than the physiologically-relevant doses (0.1-0.3 mg) that perform comparably in trials.
Most studied for
Coverage pending
PubMed coverage
Coverage pending
Safety profile
In your full report
Mechanism class
Endogenous hormone produced primarily by the pineal gland in response to darkness; signals biological...
Study coverage
Study coverage by goal
PubMed counts for Melatonin grouped by the goal each study targets.
Evidence overview is temporarily unavailable for Melatonin.
Evidence
What the evidence covers
The terrain of the published literature, not its conclusions.
Melatonin is one of the most-widely-used over-the-counter sleep supplements globally, with a research base spanning sleep onset latency, jet lag adjustment, shift-work sleep disorder, delayed sleep phase disorder, age-related sleep changes, and circadian rhythm disorders in blind individuals and certain neurodevelopmental conditions. The endogenous hormone is produced by the pineal gland in response to darkness, peaking in the middle of the biological night. Supplemental melatonin acts on MT1 and MT2 receptors in the brain to mimic the dark-signal and shift the circadian phase, which is mechanistically distinct from sedative-style sleep medications.
The outcome dimensions covered most heavily are sleep onset latency (the most-studied effect, examined across many trial designs and populations), jet lag prevention and treatment, shift-work sleep, age-related sleep changes (where endogenous melatonin production has declined), and circadian rhythm disorders in specific populations. Newer research streams include melatonin in autism spectrum disorder, anxiety contexts, and antioxidant/anti-inflammatory effects at much higher doses than sleep applications. The supplement-vs-physiological dose mismatch is a recurring topic in the literature: most consumer supplements provide 1-10 mg, while physiologically-relevant trials have used 0.1-0.3 mg, with research examining whether higher doses provide additional benefit for sleep timing.
Demographically, the literature is unusually broad across ages: pediatric populations feature heavily in delayed sleep phase and autism-related sleep research; older adults feature in age-related sleep decline studies; healthy adults dominate jet-lag and shift-work research. Sustained-release vs. immediate-release formulations is an active area, with immediate-release favored for sleep onset and sustained-release favored for sleep maintenance. Timing of administration matters more than dose for most outcomes - taking melatonin 1-2 hours before desired sleep onset typically outperforms taking it at bedtime.
Safety
Safety summary
Common adverse events, drug interactions, and special populations.
Melatonin has an unusually clean short-term safety profile and is sold over-the-counter in the United States and many other countries (it is prescription-only in some European countries and the UK). The most-common short-term adverse events at typical supplement doses are mild and transient: morning grogginess, headache, vivid dreams, and mood changes. Long-term safety data are limited but reassuring at typical doses; no established tolerable upper limit exists. Drug interactions to note include sedatives and CNS depressants (additive effects), anticoagulants (theoretical interaction with platelet function), antihypertensives (additive blood-pressure-lowering observed in some trials), and immunosuppressants (theoretical concern). Pregnancy and breastfeeding safety is not well-established. People taking the above medications, those with autoimmune conditions, and those pregnant or breastfeeding should consult a clinician before use.
This summary is informational and not medical advice. Consult a clinician before starting or changing any supplement, especially if you take prescription medications.
Foundations
Foundation of the evidence base
A few studies the field anchors on. Not the full picture, just the starting points.
Umbrella review specifically on melatonin, synthesizing evidence across all health outcomes and biological mechanisms in a single supplement-level reference document. The field's clearest 'what does the literature say overall' anchor for melatonin.
View on PubMedMost recent comprehensive meta-analysis on melatonin's effect on sleep quality, the supplement's primary established consumer use. Establishes the modern reference for the most-asked melatonin question.
View on PubMed
Limitations
What this page doesn't answer
Where the public summary stops and the personalized report begins.
This page summarizes the melatonin literature at a general level. It does not address what dose is appropriate for your specific goal (the evidence-aligned answer is often much lower than typical over-the-counter products provide), what timing of administration suits your situation, whether immediate-release or sustained-release is right for you, or how melatonin interacts with the medications you take. The dose mismatch between consumer products and physiologically-relevant trial doses is one of the most-practical questions the personalized report can address with your specific context.
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