Clinical uses of melatonin: evaluation of human trials.
Sánchez-Barceló, E J, Mediavilla, M D, Tan, D X et al. · Current medicinal chemistry · 2010 · DOI
Quick Summary
This review looked at 20 years of clinical trials testing whether melatonin (a natural hormone that regulates sleep) could help treat various diseases. The researchers found that melatonin appears to be safe and helpful for sleep problems and certain conditions, but more research is needed to confirm whether it helps with chronic fatigue syndrome and other illnesses.
Why It Matters
ME/CFS is explicitly identified as a condition where melatonin's therapeutic potential warrants further investigation. This review is important because it systematically evaluates melatonin's safety profile (consistently low toxicity) and identifies which conditions have sufficient evidence to justify clinical use, providing a framework for determining whether ME/CFS meets that threshold and what additional research is needed.
Melatonin showed well-founded adjuvant benefits for macular degeneration, glaucoma, gastric mucosal protection, irritable bowel syndrome, hypertension, diabetes, and chemotherapy/radiation side effects.
Preliminary evidence suggests potential utility in fibromyalgia and chronic fatigue syndrome, but this remains unconfirmed.
Data on autoimmune conditions (rheumatoid arthritis, ulcerative colitis, Crohn's disease) were ambiguous or negative.
Melatonin demonstrated very low toxicity across a wide range of doses in the majority of studies reviewed.
Inferred Conclusions
Melatonin is a safe, low-toxicity agent suitable for adjuvant use in specific conditions with established evidence, particularly sleep and circadian disorders.
Chronic fatigue syndrome and fibromyalgia represent preliminary-evidence areas requiring additional rigorous clinical trials before clinical recommendations can be made.
Melatonin's mechanisms and clinical benefit in autoimmune and inflammatory conditions require clarification through further research.
Remaining Questions
What is the optimal dose and duration of melatonin treatment for ME/CFS, and does it differ from other conditions?
What This Study Does Not Prove
This review does not establish that melatonin is effective for ME/CFS—the authors explicitly state that only preliminary data exist and more clinical studies are required. The review is a literature synthesis rather than a new clinical trial, so it cannot definitively prove efficacy in any condition; it can only summarize what existing trials have shown. Lack of reported aggravation does not prove safety in all populations or at all doses.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →