Melatonin Research

This systematic review and dose-response meta-analysis of 26 RCTs (1,689 observations) investigated the optimal dose and timing of melatonin for sleep promotion in both insomnia patients and healthy volunteers. The analysis covered trials from 1987 to 2020.

The key finding was that melatonin gradually reduces sleep onset latency and increases total sleep time, with effects peaking at 4 mg/day. Crucially, the timing of administration significantly predicted outcomes: taking melatonin 3 hours before the desired bedtime and at a dose of 4 mg/day outperformed the standard practice of 2 mg taken 30 minutes before bed.

This study provides actionable dosing guidance that challenges common practice, suggesting many people may benefit from both a higher dose and earlier administration than typically recommended.

This systematic review and meta-analysis evaluated the efficacy and safety of melatonin for treating idiopathic chronic insomnia in children and adolescents. The researchers searched multiple databases and included randomized controlled trials comparing melatonin to placebo.

The analysis found that melatonin improved sleep quality (measured by parent-reported outcomes) and reduced sleep onset latency compared to placebo. The evidence was graded as low certainty using GRADE methodology, primarily due to risk of bias and imprecision in the included studies.

Based on their findings, the authors developed clinical recommendations for the use of melatonin in pediatric populations with idiopathic insomnia, emphasizing that behavioral interventions should remain first-line treatment before considering melatonin supplementation.

This systematic review and meta-analysis examined melatonin's efficacy for chronic insomnia in children and adolescents with underlying neurodevelopmental or psychiatric disorders, including autism spectrum disorder (ASD), ADHD, and other conditions.

The analysis pooled data from randomized controlled trials and found that melatonin improved sleep outcomes across multiple disorder categories. Children with ASD showed particularly consistent improvements in sleep onset latency and total sleep time. The evidence strength varied by condition, with stronger support for some populations than others.

The authors developed clinical recommendations acknowledging that melatonin may be especially valuable in these populations where behavioral interventions alone are often insufficient. They emphasized the importance of addressing the underlying disorder while using melatonin as an adjunctive treatment.

This systematic review comprehensively assessed the safety profile of melatonin in children and adolescents, examining both short-term and long-term adverse effects from randomized controlled trials and observational studies.

The review found that melatonin was well-tolerated in the short term, with no significant increase in serious adverse events compared to placebo. Common mild side effects included morning drowsiness, headache, and dizziness, but these were generally comparable to placebo groups. The evidence for long-term safety was limited due to the short duration of most available studies.

Using GRADE methodology, the authors assessed the certainty of evidence for various adverse outcomes. They concluded that while short-term use appears safe, clinicians should remain cautious about prolonged use in children given the lack of robust long-term data, particularly regarding effects on pubertal development.

This systematic review and meta-analysis examined 24 RCTs evaluating melatonin for chronic insomnia, including both non-comorbid and comorbid insomnia across different age groups. The review searched Ovid-MEDLINE, EMBASE, and Cochrane Library through November 2020.

Notably, the analysis found age-dependent effects: melatonin significantly reduced sleep onset latency and improved total sleep time in children and adolescents, but was not significantly effective in adults with non-comorbid chronic insomnia. For comorbid insomnia, melatonin improved sleep onset latency across all age groups, though adult data was limited to a single study.

This study challenges the assumption that melatonin is equally effective across all populations for chronic insomnia, suggesting its primary utility may be in pediatric sleep disorders and circadian-related issues rather than chronic adult insomnia.

This systematic review and meta-analysis examined 23 RCTs (from 2,642 screened papers) evaluating melatonin supplementation's effect on sleep quality using the Pittsburgh Sleep Quality Index (PSQI). The study provides condition-specific evidence for melatonin's efficacy.

Overall, melatonin significantly improved sleep quality (WMD: -1.24, 95% CI: -1.77 to -0.71, p < 0.001), though with substantial heterogeneity (I-squared = 80.7%). Subgroup analysis revealed the strongest effects in patients with respiratory diseases (WMD: -2.20) and metabolic disorders (WMD: -2.74), with more modest effects in primary sleep disorders (WMD: -0.67).

Importantly, melatonin did not significantly improve sleep quality in people with mental disorders, neurodegenerative diseases, or certain other conditions, suggesting its benefits are condition-dependent rather than universal.

This comprehensive meta-analysis examined 19 randomized controlled trials involving 1,683 participants to evaluate melatonin's effects on primary sleep disorders. It represents one of the most rigorous analyses of melatonin's sleep benefits.

The analysis found statistically significant improvements in sleep latency, total sleep time, and subjective sleep quality, establishing melatonin as an effective intervention for sleep disorders.

This meta-analysis from MIT and other institutions examined 17 controlled studies to determine the effects of exogenous melatonin on sleep parameters. The study included prominent melatonin researcher Richard Wurtman among its authors.

The analysis provided strong evidence for melatonin's efficacy across multiple sleep parameters and importantly found no evidence of tolerance development or withdrawal effects with continued use.

This Cochrane systematic review evaluated all available randomized controlled trials on melatonin for jet lag prevention and treatment. It remains a foundational reference for melatonin's use in circadian disruption.

The review concluded that melatonin is remarkably effective, with the majority of trials showing significant benefit. The effect is greater for eastward travel and when crossing more time zones.