Downey, D C · Medical hypotheses · 1992 · DOI
This study examined 19 patients with severe fatigue who showed unusual reactions to copper-containing bracelets or necklaces. The researchers found that 8 of these patients had deficiencies in enzymes related to heme (a component of blood), and suggested that problems with copper metabolism and heme processing might explain fatigue in conditions like ME/CFS, multiple sclerosis, and other disorders.
This work raises the possibility that ME/CFS may share underlying biochemical abnormalities—particularly in heme metabolism—with other recognized conditions, which could open new avenues for diagnostic testing and treatment. If heme pathway deficiencies are confirmed in larger cohorts, it could provide a biological basis for fatigue syndromes currently considered idiopathic.
This study does not prove that copper exposure or heme deficiency causes ME/CFS; it presents only correlational observations in a small, uncontrolled group without blinded assessment or appropriate controls. The abnormal responses to copper bracelets are not validated objectively, and the proposed link between copper sensitivity and heme pathway deficiency remains speculative and untested mechanistically.
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 →
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Primary citation
Downey, D C (1992). Fatigue syndromes: new thoughts and reinterpretation of previous data.. Medical hypotheses. https://doi.org/10.1016/0306-9877(92)90184-e
BibTeX
@article{mecfsatlas-downey-1992-fatigue-syndromes,
author = {Downey, D C},
title = {Fatigue syndromes: new thoughts and reinterpretation of previous data.},
journal = {Medical hypotheses},
year = {1992},
doi = {10.1016/0306-9877(92)90184-e},
note = {PubMed: 1461185},
url = {https://www.mecfsatlas.com/evidence/downey-1992-fatigue-syndromes},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/downey-1992-fatigue-syndromes
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