PEDEvidence

Melatonin

What it is & what research shows

Study example available

Melatonin is a hormone involved in the body’s timing of sleep. The trial below studied a prolonged-release formulation, not every melatonin supplement. 354 adults aged 55–80 with insomnia were randomized to prolonged-release melatonin 2 mg or placebo, one tablet daily two hours before bedtime for three weeks. [1.1]

Selected human research: 354 adults aged 55–80 with insomnia were randomized to prolonged-release melatonin 2 mg or placebo, one tablet daily two hours before bedtime for three weeks. Combined improvement in sleep quality and morning alertness occurred in 26% versus 15%. Reported time to fall asleep fell by 24.3 minutes versus 12.9 minutes with placebo. Short trial in older adults using one formulation. Findings do not establish the effects of immediate-release products, higher doses or treatment in younger people. The abstract does not provide detailed adverse-event rates. This is a selected trial summary, not a full literature review or formal quality appraisal. [2.1]

Studied methods, not dosing advice. Selected evidence, not a complete literature review or formal quality appraisal.
Sources & reading scope

Study-summary coverage

No completed study summaries are linked to this compound page yet. This is a coverage gap on PED Evidence, not evidence that human studies or other research do not exist.

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Selected study reading notes

Source-linked summaries with studied methods. These are separate from the automated summary counts above and are not formal quality appraisals.

Human

Melatonin: what did the insomnia trial show?

354 adults aged 55–80 with insomnia were randomized to prolonged-release melatonin 2 mg or placebo, one tablet daily two hours before bedtime for three weeks.

Demonstrated findings

Combined improvement in sleep quality and morning alertness occurred in 26% versus 15%. Reported time to fall asleep fell by 24.3 minutes versus 12.9 minutes with placebo.

Limitations & adverse findings

Short trial in older adults using one formulation. Findings do not establish the effects of immediate-release products, higher doses or treatment in younger people. The abstract does not provide detailed adverse-event rates.

What might this mean? · interpretation

These results apply to the studied population, formulation and follow-up.

What might this mean, and what would change the interpretation?

This is a selected trial summary, not a full literature review or formal quality appraisal.

What would clarify this: Further studies of long-term outcomes and different patient groups.

Findings reviewed · abstract

Checked Sep 23, 2026 against the linked abstract. This reading note is not a formal risk-of-bias appraisal.

More about Melatonin: identity, safety & reference details
Small moleculeBrain & cognition
Primary research area
Sleep · insomnia
Regulatory status
See formulation-specific sources
Evidence level
Human randomized trials
Primary mechanism
Melatonin hormone
Reference profile available · Coverage varies by section

What has been observed?

Selected source-linked reading notes, not the complete literature or a pooled conclusion.

Human · Abstract reviewed

Melatonin: what did the insomnia trial show?

354 adults aged 55–80 with insomnia were randomized to prolonged-release melatonin 2 mg or placebo, one tablet daily two hours before bedtime for three weeks.

Combined improvement in sleep quality and morning alertness occurred in 26% versus 15%. Reported time to fall asleep fell by 24.3 minutes versus 12.9 minutes with placebo.

Limits & adverse findings: This is a selected trial summary, not a full literature review or formal quality appraisal. Short trial in older adults using one formulation. Findings do not establish the effects of immediate-release products, higher doses or treatment in younger people. The abstract does not provide detailed adverse-event rates.

Open primary source · Read interpretation separately
Explore outcomes for this compound
Uses & research

354 adults aged 55–80 with insomnia were randomized to prolonged-release melatonin 2 mg or placebo, one tablet daily two hours before bedtime for three weeks. [1]

Known half-life

No source-verified value in this profile yet. A treatment schedule or duration of an effect is not a drug half-life.

Half-life describes how quickly the measured drug concentration falls by half. It does not set a dosing interval.
Evidence & important limits

Short trial in older adults using one formulation. Findings do not establish the effects of immediate-release products, higher doses or treatment in younger people. The abstract does not provide detailed adverse-event rates. [1]

Safety & evidence boundaries

Source-specific information, not a personal safety clearance or monitoring plan.

Short trial in older adults using one formulation. Findings do not establish the effects of immediate-release products, higher doses or treatment in younger people. The abstract does not provide detailed adverse-event rates.

Human study: Short trial in older adults using one formulation. Findings do not establish the effects of immediate-release products, higher doses or treatment in younger people. The abstract does not provide detailed adverse-event rates. Source

Explore safety questions by system

These are literature filters, not claims that this compound causes each effect. A keyword match is not a confirmed adverse reaction.

Interactions, rare harms, long-term effects and reversibility require separate evidence. Do not infer they are absent when the sources here do not address them.

Identity, names & formulations

Canonical compound: Melatonin · melatonin

No additional aliases recorded.

Names share a parent research page. Different esters, salts, routes and brands are not assumed to have the same half-life, indication or exposure.

Combination evidence stays attached to the studied combination. It is not automatically assigned to each ingredient.

Understand the evidence types

Read the model and design first, then the population, outcome and limitations. These categories describe evidence, not a best-compound ranking.

Randomized human trials
Compare assigned interventions. Randomization does not by itself establish low bias or relevance to every population.
Controlled human studies
Use a comparison group; allocation and confounding still matter.
Prospective human research
Follows participants forward. It may be observational or interventional, so this is not a separate quality grade.
Observational human research
Describes associations. Confounding can explain differences.
Case reports and series
Useful for unusual events and safety signals, not reliable rates or effect sizes.
Animal research
Can test biology and function in a living model. Human exposure, benefit and safety remain separate questions.
Cell and tissue research
Tests responses in a preparation, including human-derived cells. It is not a human participant trial.
Mechanistic and computational evidence
Helps explain or predict a pathway; predictions need experimental and clinical testing.
Anecdotal reports
Self-reported experiences can generate questions. Product identity, selection bias and other interventions may be uncontrolled.

Systematic reviews synthesize studies and depend on their quality. Preprint status and abstract versus full-paper reading are separate labels. Citation popularity measures attention, not reliability. A study summary is not a formal quality appraisal.

Sources for this profile

  1. 1. Prolonged-release melatonin in insomnia patients aged 55–80 Human randomized trial · abstract

Reference facts checked 2026-09-23. Source scope is listed above; this is not a formal quality appraisal. See each label for full prescribing information.

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Study model describes the source. Confidence depends on methods, replication, population and outcome.

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