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Melatonin

Melatonin

Best for

Fall asleep sooner

Proven benefit <1–52 weeks 8 meta-analyses, n=4k #1 of 20 studied

  • 101 papers
  • 9 of 168 outcomes
  • 7 positive
  • 8 severe

Melatonin provides a proven benefit for falling asleep faster, with the clearest evidence focused on sleep onset rather than staying asleep or waking refreshed.

Median effective dose, most-studied outcomes

  • Sleep more soundly 5 mg 1–104 wk
  • Spend more time asleep 5 mg <1–52 wk
  • Fall asleep sooner 5.25 mg <1–52 wk
Full protocol, 11 outcomes

Risk, worst reported severity

  • fatigue severe
  • insomnia severe
  • lipid modifying agents moderate
  • metformin moderate
All 18 events and interactions

What melatonin actually does

Outcome Effect Evidence Dose Time Rank
Clear benefits 1
Fall asleep sooner Proven benefit A shorter wait for sleep can make bedtime feel less frustrating.
moderate 		8 meta-analyses 28 papers · n=4.0k — 0–52 wk #1 /20
Modest benefits 3
Sleep that feels more restorative Proven modest benefit Sleep quality reflects whether the night leaves you feeling well rested.
small 		10 meta-analyses 29 papers · n=6.1k — 1–104 wk #2 /34
Get more sleep each night Likely modest benefit More time asleep can help you meet the amount of sleep you need.
small 		10 meta-analyses 25 papers · n=3.8k 0.3–24 mg 0–52 wk #2 /9
Wake up more refreshed Proven modest benefit Feeling alert in the morning can make the day easier to start.
small 		3 meta-analyses 19 papers · n=1.4k — 0–17 wk #1 /16
Worth watching 2
Ease jet lag Promising early signal Jet lag can disrupt sleep and alertness after travel across time zones.
moderate 		2 meta-analyses 9 papers · n=1.1k 0.3–8 mg 0–6 wk #1 /3
Reduce insomnia symptoms Promising early signal Less severe insomnia can mean fewer nights spent struggling with sleep.
moderate 		6 RCTs 6 papers · n=364 0.5–20 mg 2–17 wk #1 /13
Early research 3
Stay asleep through the night Studies contradict Uninterrupted sleep helps the night feel more settled and restorative.
moderate 		7 meta-analyses 18 papers · n=816 0.3–24 mg 4–52 wk —
Spend more time in deep sleep Faint early signal Deep sleep is a stage of sleep linked with physical restoration.
small 		2 RCTs 2 papers · n=24 0.3–9 mg 4–12 wk #4 /6
Spend more time in REM sleep Not enough research REM sleep is the sleep stage most closely associated with vivid dreaming.
— 		1 meta-analysis 2 papers · n=139 2–10 mg 4–10 wk —

Effect tiers come from native-unit MCID where available, Cohen's d otherwise.

Protocol

Dose, timing & forms

How much

For falling asleep faster, oral trials span a wide range, from 0.3 to 12 mg, with a median effective dose of 5.25 mg across the better-performing studies. 12 Sleep quality and total sleep time trials also commonly center around 5 mg, but their average improvements are smaller than the effect on sleep onset. 12 Study periods range from days to a year, although the middle of the evidence sits around four to eight weeks. 12

When and how long

Match the dose to the bedtime you want to keep. Melatonin works as a clock cue, so consistency matters more than treating it like an occasional middle-of-the-night rescue. 4 For a shifted schedule or jet lag, align it with the intended local bedtime and give your body several nights to adjust. 34

Forms & standardisation

Most sleep research uses oral melatonin, but release speed matters. Immediate-release products fit the goal of falling asleep, while extended-release products aim to keep the signal going later into the night. 24 Check whether a label identifies the release type and the amount per serving, since a product marketed simply as melatonin does not tell you how quickly it releases its dose.

Studied range, by outcome

Outcome Studied range Median effective Duration Evidence
Sleep more soundly — 5 mg 1–104 wk 28 papers 20 sig. endpoints
Spend more time asleep 0.3–24 mg 5 mg <1–52 wk 25 papers 17 sig. endpoints
Fall asleep sooner 0.3–12 mg 5.25 mg <1–52 wk 24 papers 20 sig. endpoints
Feel alert through the day — 5.25 mg <1–17 wk 19 papers 10 sig. endpoints
Stay asleep through the night 0.3–24 mg 5 mg 4–52 wk 18 papers 13 sig. endpoints
Shift sleep and wake times earlier 0.3–6 mg 3.15 mg <1–6 wk 6 papers 14 sig. endpoints
Sleep more easily through the night 0.5–20 mg 3 mg 2–8 wk 4 papers 4 sig. endpoints
Adjust to local time sooner 0.5–8 mg 5 mg 1 wk 3 papers 5 sig. endpoints
Support overnight physical recovery 0.3–9 mg 9 mg 4–12 wk 2 papers 1 sig. endpoint
Support healthy REM sleep 2–10 mg — 4–10 wk 2 papers
Support healthy stage N2 sleep 0.3–5 mg 2.65 mg 12 wk 1 paper 2 sig. endpoints

Adverse events and drug interactions

Safety events

fatigue severe
insomnia severe
major side effects (severe dizziness, vivid nightmares, crippling drowsiness, severe headache, behavioral changes, pain worsening) severe
major side effects (combination arm: severe dizziness, vivid nightmares, drowsiness, severe headache, behavioral changes, pain worsening) severe
drowsiness severe
nausea severe
stroke (acute ischemic event) severe
severe sedation / somnolence severe

Drug interactions

other moderate decreases effect
lipid modifying agents moderate increases effect
metformin moderate increases effect
blood glucose lowering moderate increases effect
antineoplastic agents moderate increases effect
hypnotics and sedatives moderate additive
other moderate increases concentration
antithrombotic agents moderate increases toxicity
antihypertensives moderate decreases effect
antithrombotic agents moderate increases toxicity
Buy well

Recommended Melatonin products

Real products that dose Melatonin where the research does, in a clean formulation, from brands we've audited. We only list ones we'd stand behind.

Chosen for adequate Melatonin dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

In context

What this is and how it works

  • Across 28 studies (n=3,962), melatonin improved sleep-onset outcomes, with positive effects reported across 50 endpoints.1
  • The evidence base reviewed here spans 101 papers and 168 outcomes, including sleep, circadian timing, and jet lag.2
  • Benefits are strongest for delayed sleep timing and schedule disruption, while effects on sleep quality are smaller and less consistent.1

Melatonin is a hormone your brain releases as evening darkness arrives. Supplemental melatonin gives that nighttime signal a louder voice, which is why people use it when bedtime, travel, or shifting schedules throw their internal clock off course. 4

Melatonin attaches to MT1 and MT2 receptors that help set the timing of your sleep and wake rhythm. Think of it as changing the timestamp on your brain's daily calendar, telling it that night has arrived rather than sedating it like a switch. 4

Bottom line

Melatonin makes the most sense when your main problem is falling asleep later than you want, or when travel and schedule changes have scrambled bedtime. 13 Keep expectations realistic for staying asleep and waking refreshed, where benefits are smaller and studies disagree more. 12 Skip self-experimenting if it leaves you severely drowsy, dizzy, or troubled by vivid nightmares, and check with a clinician or pharmacist if you use regular medication.

Frequently asked

Common questions

How long does melatonin take to work?

For sleep onset, take melatonin before the bedtime you are aiming for, rather than after a long stretch of wakefulness in bed. Trials show its clearest benefit is shortening the time it takes to fall asleep. 12

Does melatonin help you stay asleep all night?

The answer is less clear than it is for falling asleep. Some studies show longer or more continuous sleep, but results for nighttime awakenings disagree across dose, duration, and participant groups. 12

Is melatonin useful for jet lag?

Early evidence suggests melatonin can help shift your sleep schedule toward local time after travel, especially when you take it according to the destination bedtime. The jet lag evidence is promising, but less settled than the evidence for falling asleep faster. 34

Sources

Sources

  1. 1. Meta-Analysis: Melatonin for the Treatment of Primary Sleep Disorders (2013) ↑
  2. 2. Evidence for the Efficacy of Melatonin in the Treatment of Primary Adult Sleep Disorders (2017) ↑
  3. 3. The Prevention and Treatment of Jet Lag (2002) ↑
  4. 4. New Perspectives on the Role of Melatonin in Human Sleep, Circadian Rhythms and Their Regulation (2018) ↑

Generated August 27, 2026

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