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Melatonin

Sleep

StrongFor the population and outcome described, multiple large human trials broadly agree.

A timing signal, not a sedative. Best evidence is for shifting your clock, not knocking you out.

0.1-0.3 mg
Doses described as physiologic in the literature, most shelf products sell 3-10 mg

What it is

The hormone your brain releases as darkness falls, a timing signal more than a sedative. That distinction explains a lot: the doses on shelves are far above what circadian research uses, and bigger doses do not reliably mean better sleep.

How it works

Melatonin signals your body clock. WHEN it is taken relative to your own rhythm determines whether it shifts your clock earlier or later, which is why timing is genuinely complicated and depends on travel direction and your current schedule, and why it is worth reading a jet-lag protocol or asking a clinician rather than guessing. The sleep-onset effect itself is real but modest in trials: roughly 7-12 minutes faster on average.

Which form to buy

Low-dose immediate release (0.3-1 mg)Circadian timing

Near the range used in clock-shifting research (physiologic exposure is often described as lower still, ~0.1-0.3 mg). Jet-lag trials have used anywhere from 0.5-5 mg.

The range circadian research works in.

Standard 3-10 mg tabletsWhat shelves stock

Far above physiologic exposure. A 2024 dose-response analysis put peak sleep-promoting effect nearer 4 mg, so "more is always worse" is too simple, but higher doses do associate with more next-day grogginess.

Common, and not automatically wrong for sleep, but not a circadian dose.

Extended releaseMiddle-of-night waking

Designed to hold levels through the night; the prescription version abroad targets adults over 55.

Sensible if your problem is staying asleep rather than falling asleep.

GummiesCaution

Analyses have found gummy melatonin content well off label, and pediatric ingestions have risen sharply.

Worth storing like medication if children are around.

What it actually does, graded

Jet lagStrong

The best-supported use, correctly timed doses reliably help adaptation across time zones.

Delayed sleep-wake phase disorderLimited

Sleep-medicine guidelines give it only a WEAK recommendation here, on low-quality evidence.

Falling asleep fasterModerate

Meta-analyses find a real but modest reduction in time to fall asleep, minutes, not hours.

Shift-work sleepLimited

Findings across trials are inconclusive; timing appears to matter more than dose.

Total sleep timeLimited

Small increases at best; this is not what melatonin is good at.

A sedative for general insomniaLimited

Sleep guidelines generally do not recommend it as a first-line insomnia treatment. CBT-I outperforms it.

Pros and cons

Pros
  • Genuinely excellent at the one thing it does best: moving your clock
  • Cheap, and the effective dose is the small one
  • Not habit-forming in the way sedative sleep drugs are
Cons
  • US supplement content is notoriously unreliable, one analysis found the large majority of products off their label
  • Typical shelf doses are 10-30x physiological
  • Grogginess and vivid dreams are commonly reported, more so at higher doses
  • Timing drives much of the effect and is genuinely complicated, the label never explains it

What to expect

  • Jet lag: benefit is reported over the first nights after arrival, though subjective sleep improving is not the same as a measured clock shift.
  • Ongoing (sleep onset): expect minutes off your time to fall asleep, not a switch being flipped.
  • Morning after a high dose: grogginess and unusually vivid dreams are the commonly reported downside.

Interactions

CautionBlood thinners (warfarin and similar)Reports of altered clotting; prescriber should know before regular use.
CautionSedatives, sleep medication, alcoholAdditive drowsiness.
AvoidFluvoxamineDramatically raises melatonin levels by blocking its breakdown.
CautionNifedipineIn a human crossover trial melatonin RAISED blood pressure and heart rate on this drug, the specific antihypertensive with real evidence.
MonitorEstrogen-containing contraceptives / HRT, and quinolone antibioticsThese can raise melatonin exposure by slowing its breakdown.
MonitorCarbamazepine, phenytoin, rifampicin, smokingThese speed melatonin clearance, lowering exposure.
TimingDriving or machineryTake it when you are done for the night, the grogginess is real.

Is it for you?

Probably worth it if
  • Jet lag, or a sleep schedule that has drifted late
  • Night-shift work you are trying to sleep around
  • You want to understand the smallest-intervention option before considering sleep medication
Probably skip it if
  • You want to be knocked out, that is not what this hormone does
  • Your insomnia is chronic and ongoing; CBT-I is the better-supported route

Who should avoid it

  • Anyone on fluvoxamine
  • People on anticoagulants, without their prescriber knowing
  • Households with young children, unless it is stored like medication, pediatric ingestions have risen sharply

Research on this supplement

Papers about this supplement, not proof of the claims above. A title says what was studied, which is sometimes a negative result or a different question entirely.

  • Melatonin Use in the ICU: A Systematic Review and Meta-Analysis
    Crit Care Med, 2025
  • Optimizing the Time and Dose of Melatonin as a Sleep-Promoting Drug: A Systematic Review of Randomized Controlled Trials and Dose-Response Meta-Analysis
    J Pineal Res, 2024
  • Effect of melatonin supplementation on sleep quality: a systematic review and meta-analysis of randomized controlled trials
    J Neurol, 2022

What the evidence says

Large human evidence for jet lag and delayed sleep phase. Effects on staying asleep are much weaker than the label implies.

What studies used

0.5-3 mg; most retail doses are far higher than trials use. 30-90 min before target sleep time.

Reported from published studies and product labelling — a record of what was used in research, not a recommendation. What is right for you is a conversation with a clinician.

Watch out for

  • More is not better, high doses can worsen grogginess
  • Shifts your body clock; timing matters more than dose

Evidence base

S37,596 research papers
established literature

Large human evidence base: several phase 3 or 4 trial reports, plus multiple meta-analyses or systematic reviews.

This letter measures how much human research exists, not whether it works for you — the tier above (Strong) is the read on quality.

Research (12)

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Where next

Every supplement in the catalogThe full shelf, grouped and evidence-tiered.→The compound indexSteroids, nootropics and research chemicals.→The peptide indexInjectable peptides and what trials used.→