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Melatonin and sleep quality: grade C

Limited evidence. Direction: Benefit.

C LimitedSubjective outcome only

Educational guidance, not medical advice

Why this grade

Rubric condition met: Results only in clinical populations being extrapolated to healthy adults (C)

A meta-analysis of 23 trials in adults with various diseases found a 1.24-point improvement on the Pittsburgh Sleep Quality Index, with high heterogeneity and no effect in some disease groups. A meta-analysis in diagnosed primary sleep disorders found a small improvement in overall sleep quality. Both are clinical populations and the measures are self-reported, so the proposal for healthy adults is C.

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)2010201520202025Meta-analysisFerracioli-Oda 2013, 2013: meta-analysis, n = 1,683, result not recordedFatemeh 2022, 2022: meta-analysis, n not recorded, result not recorded
each study this grade rests on, by publication year and design. Solid: effect versus the comparator; half-filled: mixed; hollow: no effect; dashed: result not recorded yet. Larger marks had more participants.
Show the numbers
StudyYearDesignParticipantsResult
Ferracioli-Oda 20132013meta-analysis1683result not recorded
Fatemeh 20222022meta-analysisnot recordedresult not recorded

Effect of melatonin supplementation on sleep quality: a systematic review and meta-analysis of randomized controlled trials.

Fatemeh G, Sajjad M, Niloufar R. Effect of melatonin supplementation on sleep quality: a systematic review and meta-analysis of randomized controlled trials J Neurol, 2022. PMID 33417003

Result not recorded
Design
Systematic review and meta-analysis of 23 RCTs
Population
Adults with various diseases (clinical populations)
Funding
not stated

Meta-analysis: melatonin for the treatment of primary sleep disorders.

Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders PLoS One, 2013. PMID 23691095

Result not recorded
Design
Meta-analysis of 19 randomized placebo-controlled trials
Sample
n = 1,683
Population
Adults and children diagnosed with primary sleep disorders (clinical population)
Funding
Partly funded by APIRE/Eli Lilly Psychiatric Research Fellowship and AACAP/Eli Lilly Pilot Research Award (to author MHB); NIH and non-US government support per PubMed

Search and history

Search (): melatonin[ti] AND (total sleep time[tiab] OR sleep quality[tiab]) AND meta-analysis[pt]

  • Graded C (proposed): Proposed in the monograph draft
  • C to C (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page