Melatonin

Overview

Melatonin is a hormone your own pineal gland (a small gland deep in your brain) makes at night to help set your internal clock¹. As a supplement, it's the same molecule — chemically an indole-based compound related to the amino acid tryptophan — taken to help you fall asleep and sleep better.

A large analysis pooling 23 randomized controlled trials found that melatonin supplements meaningfully improved sleep quality, as measured by a standard questionnaire called the Pittsburgh Sleep Quality Index, in adults with a range of underlying health conditions². A more recent analysis pooling 26 randomized trials looked specifically at how timing and dose change the effect, finding that both matter for how much melatonin shortens the time it takes to fall asleep and lengthens total sleep time¹. Outside of sleep, researchers are also exploring melatonin's antioxidant and anti-inflammatory properties in early-stage lab and material-science work — for instance, as a slow-release ingredient in an experimental spinal-disc implant gel — but that line of research is not about taking a melatonin pill and doesn't tell us anything about oral supplement use in people³.

Dosage

The dose-response meta-analysis of 26 randomized trials found that both the dose used and the time of administration before bedtime changed how much melatonin shortened sleep onset latency (time to fall asleep) and increased total sleep time¹. The brief does not report a single specific milligram figure or timing window that was used consistently across trials — the key finding is that dose and timing both matter, not a single fixed number. No further dosage breakdown was found in the reviewed studies.

Interactions

No drug or herb interaction data was found in the reviewed studies.

Evidence Strength

This is one of the better-studied natural sleep aids on this site: two separate meta-analyses pooling roughly 23 and 26 randomized controlled trials both support an effect on sleep quality and sleep timing^2,1. That said, both are analyses of existing trials rather than brand-new large studies, and neither reports the kind of detailed side-effect or interaction data a reader would want for everyday decision-making. Other research mentioned here — on lipid metabolism in animal cells, gut bacteria in sleep-deprived mice, and a disc-regeneration gel — is early laboratory or animal work and should be read as background only, not evidence of what melatonin does in people beyond sleep.