Effect of Melatonin Plus Zinc Supplementation on Fatigue Perception in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial. — CFSMEATLAS
Effect of Melatonin Plus Zinc Supplementation on Fatigue Perception in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial.
Castro-Marrero, Jesús, Zaragozá, Maria-Cleofé, López-Vílchez, Irene et al. · Antioxidants (Basel, Switzerland) · 2021 · DOI
Quick Summary
This study tested whether taking melatonin (1 mg) and zinc (10 mg) together could help reduce fatigue in ME/CFS patients. Over 16 weeks, people taking the supplement reported feeling less physically tired compared to those taking placebo, and they also reported better overall quality of life. The supplements appeared to be safe with no serious side effects reported.
Why It Matters
ME/CFS patients have few evidence-based treatment options and frequently experience severe fatigue that limits daily functioning. This study provides preliminary evidence that a safe, inexpensive, accessible combination supplement may meaningfully reduce fatigue perception and improve quality of life, offering potential hope for symptomatic relief while research into underlying causes continues.
Observed Findings
Significant reduction in physical fatigue perception in the melatonin+zinc group versus placebo at 16-week follow-up (p < 0.05)
Significant improvement in physical component summary scores across all follow-up visits (8, 16, and 4 weeks post-treatment) in the treatment group
Urinary 6-sulfatoxymelatonin levels were significantly elevated in the melatonin+zinc group versus placebo throughout treatment (p < 0.0001)
No significant differences in serum or urinary zinc concentrations were detected between groups
No serious adverse events were reported in either group over the 16-week treatment period
Inferred Conclusions
Oral melatonin plus zinc supplementation is safe and may be effective for reducing fatigue perception and improving quality of life in ME/CFS patients over a 16-week period
Melatonin bioavailability was confirmed by urinary metabolite elevation, suggesting adequate absorption of the prescribed dose
Combination melatonin-zinc supplementation warrants further investigation in larger, longer-term controlled trials to establish clinical significance and mechanisms of action
Remaining Questions
Does the fatigue reduction persist beyond the 4-week post-treatment follow-up, or do symptoms return to baseline?
What This Study Does Not Prove
This study does not prove that melatonin and zinc treat the underlying biological causes of ME/CFS—it only shows perceived fatigue reduction in a small sample. The findings are correlational and may reflect placebo effects or natural symptom fluctuation; larger, longer-term studies with objective functional measures are needed before recommending this as standard treatment. The lack of significant zinc biomarker changes raises questions about whether zinc contributed meaningfully to the observed effects.
Tags
Symptom:Unrefreshing SleepFatigue
Biomarker:Blood Biomarker
Method Flag:Weak Case DefinitionSmall SampleExploratory Only
What is the relative contribution of melatonin versus zinc to any observed benefit—would either supplement alone be effective?
What are the underlying biological mechanisms—do improvements relate to antioxidant effects, immune modulation, sleep quality, or other pathways?
Would this combination be beneficial for ME/CFS patients with specific phenotypes or biomarker profiles, and are there predictors of treatment response?