Melatonin

What it is

Melatonin is the hormone your brain releases as light fades — the circadian signal that night has arrived. Taken 30–60 minutes before bed, supplemental melatonin delivers that signal on your schedule, which is why the evidence is clearest for falling asleep sooner and for shifting sleep timing after travel or schedule changes, and weaker for staying asleep through the night.

Because it is a timing signal rather than a sedative, dose logic runs opposite to intuition: in a dose-ranging trial, amounts as low as 0.3 mg matched 3 mg for sleep efficiency, and higher doses added next-day carryover without better sleep. Retail bottles default to 5–10 mg; our guidance starts at 0.5 mg. The table below carries the trial record.

Evidence by goal

• AA — multiple human RCTs Sleep

  Across 19 trials, melatonin shortened time to fall asleep by about 7 minutes, added about 8 minutes of total sleep, and improved rated sleep quality; nine of ten jet-lag trials favored it after flights crossing five or more time zones.

  Ferracioli-Oda E, 2013 · Brzezinski A, 2005 · Herxheimer A, 2002 · Zhdanova IV, 2001 · Costello RB, 2014

Forms compared

• Immediate release. Carries the evidence for falling asleep sooner and for shifting sleep timing. The default.
• Extended release. Aims at staying asleep through the night; the evidence for that outcome is thinner than for immediate release.

Dose and timing

Start at 0.5–1 mg, 30–60 minutes before your target bedtime. Raise the dose only if a week at the low end changes nothing, and stay at or under 5 mg — trial data show low doses matching high ones with less morning grogginess. For time-zone shifts, take it near the destination bedtime.

Evidence-backed range: 0.5–5 mg per day.

Cautions and interactions

• If you take a benzodiazepine or prescription sleep medication, do not add melatonin on your own — layered sedatives compound drowsiness and next-day carryover. Sequencing sleep aids is a job for your prescriber.
• If you take an SSRI, tell your prescriber before starting: some serotonergic medications slow melatonin breakdown, so a small dose can act like a large one. Start at the lowest dose.
• Vivid dreams are common. Avoid driving after taking it.
• Evidence in pregnancy and nursing is thin — melatonin is a hormone, so we leave it out there unless your clinician specifically suggests it.

From our interaction tables

• avoid Benzodiazepines (class). Melatonin layered on benzodiazepines compounds sedation and next-day carryover. We exclude it — sequencing sleep aids is a job for your prescriber.
• avoid Prescription sleep medication. Adding melatonin to prescription sleep medication stacks sedatives without evidence of added benefit. We exclude it; ask your prescriber about sequencing instead.
• caution SSRIs (class). Some serotonergic medications (fluvoxamine especially) slow melatonin breakdown, so a small dose can act like a large one. Start at the lowest dose and tell your prescriber.
• caution Pregnancy. Melatonin is a hormone and pregnancy safety data are thin. We leave it out unless your clinician specifically suggests it.
• monitor Caffeine. Late-day caffeine works directly against evening melatonin signaling. Keep caffeine before early afternoon if sleep timing is the goal. See the evidence

Who should skip this

• Anyone on benzodiazepines or prescription sleep medication, unless their prescriber sets the plan.
• People who are pregnant or nursing — safety data are thin.
• People who need to drive or operate machinery within a few hours of the dose.

Questions we actually get

Is a higher dose more effective?

No. In dose-ranging work, 0.3 mg matched 3 mg for sleep efficiency, and higher doses produced more next-day carryover without better sleep. More is just more carryover.

Will I become dependent on it?

The trial record at these doses has not shown a rebound or escalation pattern. That said, melatonin works on timing — if your sleep trouble is racing thoughts at 2 a.m. rather than a late-shifted clock, it is the wrong tool.

When should I take it for jet lag?

Near the destination bedtime, starting on arrival. The jet-lag evidence is for flights crossing five or more time zones.

Immediate or extended release?

Immediate release, for most people — it carries the evidence for falling asleep sooner. Extended release targets staying asleep, where the evidence is thinner.

Sources

1. Ferracioli-Oda E, Qawasmi A, Bloch MH, PLoS ONE, 2013 — meta-analysis of melatonin and sleep outcomes
2. Brzezinski A, Vangel MG, Wurtman RJ, et al., Sleep Medicine Reviews, 2005 — meta-analysis of exogenous melatonin and sleep
3. Herxheimer A, Petrie KJ, Cochrane Database of Systematic Reviews, 2002 — melatonin for jet-lag symptoms
4. Zhdanova IV, Wurtman RJ, et al., Journal of Clinical Endocrinology & Metabolism, 2001 — crossover RCT of 0.1–3 mg melatonin in older adults
5. Costello RB, Lentino CV, Boyd CC, et al., Nutrition Journal, 2014 — systematic review of melatonin for supporting healthy sleep