Magnesium deficit in a sample of the Belgian population presenting with chronic fatigue.
Moorkens, G, Manuel y Keenoy, B, Vertommen, J et al. · Magnesium research · 1997
Quick Summary
This study tested whether people with chronic fatigue have low magnesium levels. Researchers gave 97 patients a special magnesium test and found that 44 had magnesium deficiency. After magnesium supplements, their bodies retained less magnesium, suggesting the treatment may have helped. However, the researchers did not find a clear link between low magnesium and chronic fatigue syndrome itself.
Why It Matters
This study investigates magnesium status in ME/CFS patients, as magnesium plays a critical role in cellular energy production and muscle function—systems commonly impaired in ME/CFS. The finding that standard serum magnesium tests may not detect true magnesium deficiency supports the use of specialized loading tests and has implications for understanding potential metabolic dysfunction in chronic fatigue conditions.
Observed Findings
Magnesium deficit detected by IV loading test in 45% (44/97) of chronic fatigue patients
Significant decrease in magnesium retention after supplementation (p=0.0018), indicating improved magnesium status
Standard serum magnesium and red blood cell magnesium measurements showed no significant difference between magnesium-deficient and non-deficient groups
Serum magnesium levels were significantly lower in patients with spasmophilia compared to other patient groups
No significant association found between magnesium deficiency and CFS or fibromyalgia diagnosis
Inferred Conclusions
IV magnesium loading testing may detect deficiency that routine serum magnesium tests miss in chronic fatigue patients
Magnesium supplementation can restore depleted intracellular magnesium stores in deficient patients
Magnesium deficiency is not a primary defining feature of CFS or fibromyalgia but may represent a separate or secondary issue
Spasmophilia (muscle spasm syndrome) may be more strongly associated with low serum magnesium than other chronic fatigue conditions
Remaining Questions
Does magnesium supplementation improve clinical symptoms and fatigue severity in ME/CFS patients with documented deficiency?
What This Study Does Not Prove
This study does not establish that magnesium deficiency causes ME/CFS or fibromyalgia, only that it may co-occur in some patients. The lack of association between magnesium deficit and CFS/fibromyalgia diagnosis does not rule out magnesium's role in symptom management for individual patients. The small sample size (24 patients receiving supplementation) limits generalizability of the treatment response findings.
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 →