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Melatonin and total sleep time: grade C

Limited evidence. Direction: Benefit.

C LimitedShort-term only

Educational guidance, not medical advice

Why this grade

Rubric condition met: Pooled estimates mix healthy and clinical (insomnia) populations with no healthy-only estimate, and the healthy-adult trials are one single-dose crossover and one older-only trial

Pooled estimates show total sleep rising by about 8-14 minutes compared with placebo, and a Cochrane review in shift workers found about 24 minutes more daytime sleep after a night shift, rated low-quality evidence. Small placebo-controlled trials in healthy middle-aged and older adults found more sleep time or higher sleep efficiency. A 2022 meta-analysis in adults with chronic insomnia found no significant effect. The pooled estimates mix healthy and clinical groups, and the two healthy-adult trials are one single-dose crossover in 15 people and one trial in 24 adults over 55, so the grade is C.

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)1995200020052010201520202025Meta-analysisCrossover RCTFerracioli-Oda 2013, 2013: meta-analysis, n = 1,683, result not recordedLiira 2014, 2014: meta-analysis, n = 718, result not recordedBrzezinski 2005, 2005: meta-analysis, n = 284, result not recordedDuffy 2022, 2022: crossover RCT, n = 24, result not recordedAttenburrow 1996, 1996: crossover RCT, n = 15, result not recordedChoi 2022, 2022: meta-analysis, n not recorded, result not recordedCruz-Sanabria 2024, 2024: 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
Attenburrow 19961996crossover RCT15result not recorded
Brzezinski 20052005meta-analysis284result not recorded
Ferracioli-Oda 20132013meta-analysis1683result not recorded
Liira 20142014meta-analysis718result not recorded
Duffy 20222022crossover RCT24result not recorded
Choi 20222022meta-analysisnot recordedresult not recorded
Cruz-Sanabria 20242024meta-analysisnot recordedresult not recorded

High dose melatonin increases sleep duration during nighttime and daytime sleep episodes in older adults.

Duffy JF, Wang W, Ronda JM. High dose melatonin increases sleep duration during nighttime and daytime sleep episodes in older adults J Pineal Res, 2022. PMID 35436355

Result not recorded
Design
Randomized crossover trial with forced desynchrony protocol
Sample
n = 24
Population
Healthy older adults (over 55, mean 64.2 years)
Funding
Brigham Research Institute, NCRR NIH HHS M01 RR002635, NIA NIH HHS P01 AG009975, NIA NIH HHS R01 AG006072, NIA NIH HHS R01 AG044416, NIH HHS, National Institute of Research Resources, National Institute on Aging, National Institutes of Health

Low dose melatonin improves sleep in healthy middle-aged subjects.

Attenburrow ME, Cowen PJ, Sharpley AL. Low dose melatonin improves sleep in healthy middle-aged subjects Psychopharmacology (Berl), 1996. PMID 8856838

Result not recorded
Design
Randomized, placebo-controlled, double-blind crossover trial (single doses)
Sample
n = 15
Population
Healthy middle-aged volunteers
Funding
not stated

Pharmacological interventions for sleepiness and sleep disturbances caused by shift work.

Liira J, Verbeek JH, Costa G. Pharmacological interventions for sleepiness and sleep disturbances caused by shift work Cochrane Database Syst Rev, 2014. PMID 25113164

Result not recorded
Design
Cochrane systematic review and meta-analysis of 15 randomized placebo-controlled trials (9 on melatonin)
Sample
n = 718
Population
Shift workers
Funding
not stated

Efficacy of melatonin for chronic insomnia: Systematic reviews and meta-analyses.

Choi K, Lee YJ, Park S. Efficacy of melatonin for chronic insomnia: Systematic reviews and meta-analyses Sleep Med Rev, 2022. PMID 36179487

Result not recorded
Design
Systematic reviews and meta-analyses of 24 placebo-controlled RCTs
Population
Patients with chronic insomnia, all ages (clinical population)
Funding
Ministry of Food and Drug Safety, Ministry of Science, ICT and Future Planning, National Research Foundation of Korea

Optimizing the Time and Dose of Melatonin as a Sleep-Promoting Drug: A Systematic Review of Randomized Controlled Trials and Dose-Response Meta-Analysis.

Cruz-Sanabria F, Bruno S, Crippa A. Optimizing the Time and Dose of Melatonin as a Sleep-Promoting Drug: A Systematic Review of Randomized Controlled Trials and Dose-Response Meta-Analysis J Pineal Res, 2024. PMID 38888087

Result not recorded
Design
Systematic review and dose-response meta-analysis of 26 double-blind RCTs
Population
Patients with insomnia and healthy volunteers (1,689 observations)
Funding
Fondazione Arpa, Italian Ministry of Health

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

Effects of exogenous melatonin on sleep: a meta-analysis.

Brzezinski A, Vangel MG, Wurtman RJ. Effects of exogenous melatonin on sleep: a meta-analysis Sleep Med Rev, 2005. PMID 15649737

Result not recorded
Design
Meta-analysis of 17 studies
Sample
n = 284
Population
Mostly healthy subjects or people with insomnia only (15 of 17 studies)
Funding
NCRR NIH HHS 5M01 RR1066-25, National Institutes of Health

Search and history

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

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