E3 PreliminaryPreliminaryPEM unclearMachine draft
A Perspective on the Role of Metformin in Treating Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID.
Fineberg, David, Moreau, Alain, Schneider-Futschik, Elena K et al. · ACS pharmacology & translational science · 2025 · DOI
Quick Summary
This article explores whether metformin, a common diabetes medication, might help treat ME/CFS and Long COVID by fixing problems with how cells make energy and controlling inflammation. The authors explain that metformin could work by reducing harmful molecules in cells, improving how the body uses energy, and calming down overactive immune responses. However, they stress that metformin would likely work best as part of a combination treatment rather than as a single cure.
Why It Matters
This review is important because it proposes a mechanistic rationale for repurposing an affordable, well-tolerated existing medication for ME/CFS and Long COVID—conditions that currently lack disease-modifying treatments. If metformin's proposed mechanisms are validated in clinical trials, it could offer symptomatic and functional benefit to millions of patients, particularly given its existing safety profile in other populations.
Observed Findings
- Metformin inhibits complexes I and IV of the mitochondrial electron transport chain, potentially reducing strain on complex V and decreasing reactive oxygen species production
- mTOR signaling is proposed to be overactive but underperforming in ME/CFS, and metformin's downregulation of this pathway may improve energy metabolism
- Metformin possesses multiple biological properties beyond glucose control: anti-inflammatory, vascular-protective, microbiome-modulating, neuroprotective, and epigenetic effects
- ME/CFS and Long COVID share common dysfunctions in cytokine regulation, glycolysis, ATP generation, oxidative stress, gut microbiome function, and endothelial integrity
Inferred Conclusions
- Metformin's multipathway mechanisms align with known pathophysiology of ME/CFS and Long COVID, making it a rational candidate for therapeutic investigation
- Monotherapy with metformin is unlikely to be sufficient; combination therapy addressing neurological, autonomic, and immunological dysfunction will likely be necessary
- Future clinical trials are warranted to test metformin's efficacy and establish appropriate dosing and patient selection criteria
Remaining Questions
- Do ME/CFS and Long COVID patients actually show the proposed abnormalities in mTOR signaling and mitochondrial complex function that metformin is designed to address?
- What would be the optimal dose, duration, and patient subgroups for metformin treatment, and which additional therapies should be combined with it?
What This Study Does Not Prove
This is a perspective review, not a clinical trial, so it does not provide evidence that metformin actually improves symptoms or function in ME/CFS or Long COVID patients. The proposed mechanisms are theoretically plausible but remain untested in this population, and the review does not establish whether metformin's benefits would outweigh potential risks or drug interactions in practice. No patient data or efficacy outcomes are presented.
Tags
EXPLORATORYPEM UNCLEAR
Metadata
- DOI
- 10.1021/acsptsci.5c00229
- PMID
- 41189723
- Review status
- Machine draft
- Evidence level
- Early hypothesis, preprint, editorial, or weak support
- Last updated
- 9 April 2026
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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