Melatonin

Melatonin receptor agonist, Sleep aid, Chronobiotic (circadian phase regulator)

Melatonin (N-acetyl-5-methoxytryptamine)

Multiple OTC dietary supplement formulations

Experience

👥 No personal reports yet

⚕ No clinical reports yet

Log in to add your own experience.

Problems

No problems yet. Be the first to suggest one.

+ Add a problem

Titration strategies

No titration strategies yet. Be the first to suggest one.

+ Add a titration strategy

Effects

No effects listed yet. Be the first to suggest one.

+ Add an effect

Relevant anecdote

No anecdotes yet. Share a relevant one.

+ Add an anecdote

Relevant Literature

No literature entries yet.

Log in to submit relevant literature.

Summary

Classes

Melatonin receptor agonist, Sleep aid, Chronobiotic (circadian phase regulator)

Common uses

Sleep-onset insomnia (broad off-label use)▲0▼, Jet lag (off-label, evidence-supported)▲0▼, Shift-work sleep-wake disorder (off-label)▲0▼, Delayed sleep phase syndrome (off-label, evidence-supported)▲0▼, Pediatric insomnia in autism spectrum disorder and ADHD (off-label, evidence-supported)▲0▼, Perioperative anxiolysis (off-label)▲0▼

Pharmacy

Starting dose

0.5-3 mg PO 30-60 minutes before bedtime. Some patients respond to micro-doses (0.3 mg) without additional benefit at higher doses. For circadian phase shifting, timing relative to dim-light melatonin onset matters more than absolute dose

Preparations

OTC tablets, sublingual tablets, gummies, liquid, extended-release tablets and capsules; common strengths 0.5, 1, 3, 5, 10 mg

US FDA Max

Not formally established (dietary supplement); doses above ~3-5 mg show no additional efficacy but increase next-day sedation risk

Pharmacology

Routes

Oral, sublingual

Onset

30-60 minutes (immediate-release oral)

Duration

3-4 hours

Half-life

30-50 minutes (short)

Bioavailability

~15% (oral; highly variable due to extensive and variable first-pass metabolism)

Pregnancy

Limited human data; endogenous hormone, but supplemental pharmacological doses are not well characterized in pregnancy.^{[citation needed]}

Legal status

OTC dietary supplement in the US (not FDA-regulated as a medicine; multiple studies show OTC products contain 50-470% of labeled melatonin content); Rx-only in the EU and UK

Purported mechanism

Endogenous hormone secreted by the pineal gland in response to darkness, agonist at MT1 receptors (mediating sleep-onset effect and suppression of the suprachiasmatic nucleus wakefulness signal) and MT2 receptors (mediating circadian phase regulation). Pharmacological dosing supplements the endogenous nighttime peak that is suppressed by evening light exposure, fragmented by aging, or misaligned in shift work, jet lag, and delayed sleep phase syndrome.▲0▼ Functions principally as a chronobiotic rather than a sedative-hypnotic in the benzodiazepine or non-benzodiazepine-hypnotic sense, with a modest sleep-onset effect that plateaus around 3 mg/day. Sustained-release and tasimelteon (Hetlioz) are MT-receptor-selective alternatives with regulated dosing.