Compound or practice · Sleep
Melatonin
A circadian signal, not a sedative — brilliant for jet lag and shift work at low doses, mediocre as a nightly sleeping pill.
- Overall grade
- Grade B
- Last revised
- 2
- graded outcomes
- 0
- references listed
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
4 at grade B — 4 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Jet lag / circadian shiftEvidence grade B
Timing-dependent
Moderatehigh
- Sleep onset (insomnia)Evidence grade B
~7 min faster
Smallhigh
Conditions
How the entry reads its effect on diagnosed conditions: the direction first, then the grade. Never a substitute for the person who treats you.
- Jet lag ImprovesEvidence grade BBest-supported useGrade B
- Delayed sleep phase ImprovesEvidence grade BLow-dose, timedGrade B
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
Interactions
Documented pairings with supplements and medicines. A medicine on this list is a conversation for whoever prescribes it.
The evidence in words
What it is
Melatonin is the hormone the pineal gland releases in darkness to signal biological night. Supplements shift the body clock and modestly aid sleep onset.
How it works
It binds MT1/MT2 receptors to phase-shift the circadian clock and lower alertness. Because it is a timing signal, when you take it matters more than how much.
What the evidence shows
Strong for realigning the clock in jet lag and delayed sleep-phase and shift work; modest for primary insomnia (speeds onset ~7 minutes, small total-sleep gain). Most people massively overdose it — 0.3–1 mg is often as effective as 5–10 mg with fewer next-day grogginess effects.
How to use it
0.3–1 mg, 30–60 minutes before the desired sleep time (or timed to the destination clock for jet lag). Bigger is not better.
Safety & interactions
Safe short-term; grogginess and vivid dreams at high doses. It is a hormone, so caution in pregnancy and with autoimmune conditions; long-term data in children are limited. Caffeine — Opposing signals — the afternoon caffeine cutoff protects the melatonin window. Glycine — Both pre-bed and compatible. ssri — Some SSRIs (fluvoxamine) spike melatonin levels — microdose or skip.
Bottom line
Use it as a clock-setter, not a sledgehammer: 0.3–1 mg timed correctly for jet lag, shift work, or delayed sleep phase. Skip the 10 mg megadoses.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Standard
- 0.3–1 mg, 30–60 min before target sleep time.
Related reading
Entries that share this one's tags or conditions.
- Melatonin for Jet lagEvidence grade B — Best-supported useEvidence grade B
- Melatonin for Delayed sleep phaseEvidence grade B — Low-dose, timedEvidence grade B
- Melatonin for Jet lag / circadian shiftEvidence grade B — Timing-dependentEvidence grade B
- Melatonin for Sleep onset (insomnia)Evidence grade B — ~7 min fasterEvidence grade B
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.