Melatonin for Primary Sleep Disorders: A Meta-Analysis
Ferracioli-Oda E, Qawasmi A, Bloch MH
PLoS ONE • May 2013
Plain Language Summary
This large review confirmed that melatonin supplements help people fall asleep faster (about 7 minutes sooner) and improve sleep quality. Importantly, unlike many sleep aids, people don’t seem to build tolerance to melatonin – it keeps working over time. While the improvements may seem small, they’re meaningful for people who struggle with sleep onset. Melatonin is particularly helpful for jet lag and for people whose natural melatonin production is reduced (like older adults).
Key Findings
- 1Sleep onset latency reduced by 7.06 minutes (95% CI -11.77 to -2.35)
- 2Total sleep time increased by 8.25 minutes
- 3Sleep quality significantly improved
- 4Effects increased with longer treatment duration
- 5No significant tolerance developed over time
Abstract
This meta-analysis examined the effects of exogenous melatonin on primary sleep disorders. The analysis included 19 randomized, placebo-controlled studies with 1,683 participants.
Study Limitations
- Modest absolute effect sizes
- Heterogeneity in melatonin doses
- Subjective sleep outcomes in some studies
- Limited long-term data (>6 months)