Melatonin

Best for

Increase deep, restorative sleep

Large effect, needs confirmation · 0.3–9 mg/day for 4–12 weeks · 2 studies , n=24

101 papers · 10 claims · 204 outcomes scored · 9 positive

Outcomes

What melatonin actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect size Evidence Dose Weeks Rank

Increase deep, restorative sleep Large effect, needs confirmation

More time in the sleep stages where your body does its heaviest repair.

2 RCTs n=24 0.3–9 mg 4–12 wk #4/6

25862116·35436355

large

2 RCTs n=24

0.3–9 mg

4–12 wk

#4 /6

Fall asleep faster Proven benefit

Shrinks the gap between hitting the pillow and actually sleeping.

28 meta-analyses n=4.0k 0.15–12 mg 0–52 wk #1/19

15914575·16423108·20668840·20712869 +24 more

moderate

28 meta-analyses n=4.0k Meta-analyzed I²=89%

0.15–12 mg

0–52 wk

#1 /19

Stay asleep through the night Studies contradict

Fewer wake-ups and more unbroken hours of real rest.

18 meta-analyses n=2.0k 0.3–24 mg 4–52 wk #8/15

23129488·25862116·30710339·35436355 +14 more

moderate

18 meta-analyses n=2.0k Meta-analyzed I²=95%

0.3–24 mg

4–52 wk

#8 /15

Recover from jet lag faster Likely benefit

Gets your internal clock back on local time so you lose fewer days.

9 meta-analyses n=1.1k 0.3–8 mg 0–6 wk #1/2

2496815·3085768·33809656·16263827 +5 more

moderate

9 meta-analyses n=1.1k Meta-analyzed

0.3–8 mg

0–6 wk

#1 /2

Break the insomnia cycle Promising early signal

Quiets the nervous-system overdrive that keeps you wired at bedtime.

6 RCTs n=364 0.5–20 mg 2–17 wk #2/14

29912983·37267394·38816846·38846134 +2 more

moderate

6 RCTs n=364

0.5–20 mg

2–17 wk

#2 /14

Improve overall sleep quality Proven modest benefit

Deeper, less interrupted nights that leave you recharged by morning.

29 meta-analyses n=6.1k 0.5–50 mg 1–104 wk #3/37

15914575·20712869·23129488·23691095 +25 more

small

29 meta-analyses n=6.1k Meta-analyzed I²=94%

0.5–50 mg

1–104 wk

#3 /37

Sleep longer each night Likely modest benefit

More genuine sleep hours so your body finishes its repair cycles.

25 meta-analyses n=3.8k 0.3–24 mg 0–52 wk #2/12

11696071·15914575·20712869·21120122 +21 more

small

25 meta-analyses n=3.8k Meta-analyzed I²=97%

0.3–24 mg

0–52 wk

#2 /12

Wake up clear-headed Likely modest benefit

Less grogginess, more energy from the moment you open your eyes.

19 meta-analyses n=1.4k 0.3–50 mg 0–17 wk #1/14

16295212·38764237·24718775·29912983 +15 more

small

19 meta-analyses n=1.4k Meta-analyzed

0.3–50 mg

0–17 wk

#1 /14

Stay alert on long drives Barely detectable

Sharper reaction times and steadier steering when driving fatigue sets in.

5 meta-analyses n=440 0.5–10 mg 4–17 wk #2/4

24718775·29912983·32457492·37098505 +1 more

trivial

5 meta-analyses n=440 Meta-analyzed

0.5–10 mg

4–17 wk

#2 /4

Spend more time in REM sleep Not enough research

More time in the sleep stage that processes emotions and consolidates memory.

2 meta-analyses n=139 2–10 mg 4–10 wk

25862116·40387966

—

2 meta-analyses n=139 Meta-analyzed

2–10 mg

4–10 wk

—

Outcome	Effect	Evidence	Dose	Weeks	Rank
Increase deep, restorative sleep Large effect, needs confirmation	large	2 RCTs n=24	0.3–9 mg	4–12 wk	#4/6
Fall asleep faster Proven benefit	moderate	28 meta-analyses n=4.0k Meta-analyzed	0.15–12 mg	0–52 wk	#1/19
Stay asleep through the night Studies contradict	moderate	18 meta-analyses n=2.0k Meta-analyzed	0.3–24 mg	4–52 wk	#8/15
Recover from jet lag faster Likely benefit	moderate	9 meta-analyses n=1.1k Meta-analyzed	0.3–8 mg	0–6 wk	#1/2
Break the insomnia cycle Promising early signal	moderate	6 RCTs n=364	0.5–20 mg	2–17 wk	#2/14
Improve overall sleep quality Proven modest benefit	small	29 meta-analyses n=6.1k Meta-analyzed	0.5–50 mg	1–104 wk	#3/37
Sleep longer each night Likely modest benefit	small	25 meta-analyses n=3.8k Meta-analyzed	0.3–24 mg	0–52 wk	#2/12
Wake up clear-headed Likely modest benefit	small	19 meta-analyses n=1.4k Meta-analyzed	0.3–50 mg	0–17 wk	#1/14
Stay alert on long drives Barely detectable	trivial	5 meta-analyses n=440 Meta-analyzed	0.5–10 mg	4–17 wk	#2/4
Spend more time in REM sleep Not enough research		2 meta-analyses n=139 Meta-analyzed	2–10 mg	4–10 wk	—

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.

Risk profile

Adverse events and known 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

Co-studied with

Supplements that share evidence with melatonin

Sources

Generated August 14, 2026

Melatonin

What melatonin actually does, by outcome

Recommended Melatonin products

Adverse events and known drug interactions

Supplements that share evidence with melatonin

More evidence for Melatonin

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Melatonin

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Melatonin for Sleep: A Systematic Evidence Review