melatonin

Adjunctive therapy

Last reviewed 2025-12-30

Reviewed by PsychMed Editorial Team.

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Quick answers

What is melatonin?
Melatonin is an endogenous hormone that helps regulate circadian sleep-wake timing. In the United States it is commonly used as an OTC dietary supplement (not FDA-approved as a drug).
What is melatonin used for?
Label indications include: OTC dietary supplement (U.S.; not FDA-approved as a drug). Used for sleep-onset insomnia and circadian rhythm complaints (practice pattern).
What drug class is melatonin?
Endogenous sleep-wake hormone; MT1/MT2 receptor agonist. Widely used as an OTC dietary supplement for sleep-onset and circadian rhythm complaints.
What strengths does melatonin come in?
OTC products vary widely (immediate-release vs prolonged-release; 1–10+ mg strengths). Labels often recommend a bedtime dose about 30 minutes before sleep (product-dependent).

Snapshot

Primary label indications include: OTC dietary supplement (U.S.; not FDA-approved as a drug).
Class: Adjunctive therapy
Therapeutic drug monitoring not routinely recommended.
Last reviewed: 2025-12-30

Label indications

OTC dietary supplement (U.S.; not FDA-approved as a drug). Used for sleep-onset insomnia and circadian rhythm complaints (practice pattern).

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Clinical Highlights

Melatonin is an endogenous hormone that helps regulate circadian sleep-wake timing. In the United States it is commonly used as an OTC dietary supplement (not FDA-approved as a drug). It is often used for sleep-onset insomnia and circadian rhythm complaints (e.g., delayed sleep timing, jet lag). Effect sizes in insomnia studies are usually modest; a 2013 meta-analysis found small average improvements in sleep latency and total sleep time compared with placebo.

For chronic insomnia in adults, the AASM guideline recommends against routine melatonin use (weak recommendation). Many clinicians still use it as a low-risk, time-limited adjunct when the goal is sleep-onset support and substance-use risk makes controlled hypnotics undesirable.
A practical safety issue is supplement variability: analyses of OTC products have found large differences between labeled and measured melatonin content, and some products contain serotonin—so product quality matters (Erland 2017).
Melatonin is not a controlled substance and generally has low misuse potential; it does not cause respiratory depression the way opioids and sedative-hypnotics can, but next-day sleepiness can still occur.
The compare view, melatonin evidence feed, and melatonin print page can help compare OTC melatonin with prescription alternatives.

Dosing & Formulations

OTC products vary widely (immediate-release vs “extended” or prolonged-release; 1–10+ mg strengths). Many labels suggest taking one dose about 30 minutes before bedtime (product-dependent label). Start low and titrate cautiously. Many clinicians start around 0.5–1 mg for sleep-onset goals and increase only if needed, because higher doses can increase next-day grogginess without clear added benefit (clinical).

Timing is a key “dose”: taking melatonin too late can worsen morning sleepiness, and taking it at inconsistent times can reduce usefulness.
If insomnia persists beyond a short trial, prioritize CBT-I and treat comorbid contributors rather than stacking multiple sedatives.

Monitoring & Risks

Daytime sleepiness, headache, dizziness, and vivid dreams can occur; reassess driving/occupational safety if morning impairment appears (StatPearls/clinical). Because products are supplements, quality control varies; favor reputable manufacturers and avoid mixing multiple melatonin products (Erland 2017).

If mood symptoms are prominent (major depression, bipolar disorder), monitor sleep and mood trajectories—insomnia is often a symptom of the underlying condition and may not respond to supplements alone.

Drug Interactions

Melatonin is metabolized primarily by CYP1A2; potent CYP1A2 inhibitors (e.g., fluvoxamine) can increase exposure and next-day sedation risk (StatPearls). Additive sedation can occur with alcohol, cannabis, benzodiazepines, antihistamines, and other hypnotics—total sedative burden still matters even though melatonin is not GABAergic.

Practice Notes

Best fit is sleep-onset insomnia with a circadian component and low tolerance for controlled hypnotics. If frequent nighttime awakenings dominate, compare with alternatives such as DORAs or low-dose doxepin. Use melatonin as part of a sleep plan: consistent wake time, morning light exposure, and CBT-I strategies improve durability.

Reassess benefit after 1–2 weeks; if there is no meaningful improvement, stop and pivot rather than layering additional sedatives.
When supplement quality is uncertain or adherence is variable, prescription options such as ramelteon can provide more predictable dosing.

References

Melatonin tablets (dietary supplement) label — DailyMed (2025)
Melatonin (StatPearls) — StatPearls Publishing (NCBI Bookshelf) (2025)
Meta Analysis: Melatonin FOR THE Treatment OF Primary Sleep Disorders — PLoS One (PMC) (2013)
Melatonin Natural Health Products and Supplements—presence of serotonin and variability of melatonin content — Journal of Clinical Sleep Medicine (PMC) (2017)
Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline — Journal of Clinical Sleep Medicine (2017)