{ "slug": "therapeutics-me-cfs", "condition": { "name": "Myalgic Encephalomyelitis / Chronic Fatigue Syndrome", "shortName": "ME/CFS", "description": "Myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS) — a multisystem neuroimmune disorder characterised by post-exertional malaise (PEM).", "hero": "Evidence-graded therapeutic interventions for ME/CFS, including the only disease-specific RCT data and mechanistically-supported treatments." }, "page": { "title": "ME/CFS Therapeutics Evidence Atlas | OSMF", "description": "Evidence-graded therapeutic agents for Myalgic Encephalomyelitis / Chronic Fatigue Syndrome, synthesised from clinical trials, systematic reviews, and mechanistic studies.", "canonical": "https://research.opensourcemed.info/therapeutics-me-cfs.html", "dateModified": "2026-07-03" }, "categories": { "anticoagulant": "Anticoagulants & Antifibrinolytics", "immunomodulator": "Immunomodulators", "biologic": "Biologics / Monoclonal Antibodies", "mitochondrial": "Mitochondrial & Metabolic Support", "neurological": "Neurological / CNS", "nutritional": "Nutritional Supplements", "physical": "Physical / Rehabilitative" }, "tier_labels": { "1": "RCT in Long COVID / PASC / PACVS", "2": "RCT in related condition", "3": "Observational in Long COVID / PASC", "4": "Case series", "5": "Case report / expert opinion", "6": "Mechanistic / preclinical only" }, "agents": [ { "name": "Rintatolimod (Ampligen)", "alternateName": "Ampligen; poly I:poly C12U; dsRNA immunomodulator", "mechanism": "Rintatolimod is a selective TLR3 agonist that mimics double-stranded RNA (dsRNA). It activates innate antiviral immunity through TLR3/TRIF signalling, driving type I interferon production and NK cell activation. In ME/CFS, deficient TLR3 signalling and impaired NK cell cytotoxicity are documented, providing mechanistic rationale. It also inhibits 2′-5′ oligoadenylate synthetase (OAS)/RNase L pathway dysregulation observed in ME/CFS.", "mechanismTargets": [ "TLR3", "TRIF signalling", "Type I interferon pathway", "NK cell activation", "OAS/RNase L" ], "mechanismCategory": "immunomodulator", "direction": "benefit", "best_tier": 1, "tier_label": "RCT in Long COVID / PASC / PACVS", "modifier": "MIXED", "pubchem_cid": null, "evidence_summary": "Two Phase III RCTs (AMP-516, AMP-502) showed statistically significant improvement in exercise capacity and Karnofsky Performance Score vs placebo in CFS patients. FDA issued a non-approval letter citing insufficient evidence for approval in 2012 and 2016. Nevertheless, it remains the most extensively RCT-tested pharmacological agent specifically in ME/CFS. Effects appear modest and reversible on cessation.", "key_references": [ { "citation": "Strayer DR et al. J Clin Fatigue Syndr 1994", "doi": "10.1300/J092v02n02_02", "study_type": "RCT", "finding": "Rintatolimod improved exercise tolerance and physician-assessed performance in CFS (n=92 evaluable)", "year": "1994" }, { "citation": "Strayer DR et al. PLOS One 2012", "doi": "10.1371/journal.pone.0031334", "study_type": "RCT", "finding": "AMP-516 phase III: rintatolimod improved exercise capacity vs placebo (n=234); FDA declined approval", "year": "2012" } ], "key_trials": [ { "nct_id": "NCT01538212", "title": "Ampligen Phase III RCT in ME/CFS (AMP-516)", "phase": "Phase 3", "status": "Completed", "population": "ME/CFS" } ] }, { "name": "Rituximab", "alternateName": "Rituxan; MabThera; anti-CD20 monoclonal antibody", "mechanism": "Rituximab depletes CD20-expressing B cells, eliminating the source of pathogenic autoantibodies proposed to drive ME/CFS (particularly anti-GPCR autoantibodies including anti-β2-adrenergic receptor and anti-M4 muscarinic receptor). B cell depletion also reduces antigen presentation and T cell co-stimulation. The 2-phase clinical response observed in ME/CFS (initial improvement followed by relapse as B cells reconstitute) supports this autoantibody hypothesis.", "mechanismTargets": [ "CD20+ B cells", "Anti-GPCR autoantibodies", "Anti-β2-adrenergic receptor", "B cell-mediated antigen presentation" ], "mechanismCategory": "biologic", "direction": "null", "best_tier": 1, "tier_label": "RCT in Long COVID / PASC / PACVS", "modifier": "NULL", "pubchem_cid": null, "evidence_summary": "Fluge et al. Phase III RCT (RituxME, n=151, BMC Medicine 2019) failed to show significant improvement on primary endpoint (fatigue score at 18 months) despite earlier promising Phase II data. However, a biological response was observed (B cell depletion confirmed). Fluge/Mella argue B cell depletion timing and patient selection (autoantibody-positive subgroup) may determine response. The phase III failure does not rule out benefit in a biomarker-selected subgroup.", "key_references": [ { "citation": "Fluge Ø et al. BMC Med 2019", "doi": "10.1186/s12916-019-1331-5", "study_type": "RCT", "finding": "RituxME Phase III (n=151): rituximab did not significantly improve fatigue vs placebo at 18 months", "year": "2019" }, { "citation": "Fluge Ø et al. PLOS One 2015", "doi": "10.1371/journal.pone.0129898", "study_type": "RCT", "finding": "Phase II rituximab (n=30): 67% clinically significant response; median response duration 25 weeks", "year": "2015" } ], "key_trials": [ { "nct_id": "NCT02229942", "title": "RituxME: Rituximab for ME/CFS Phase III", "phase": "Phase 3", "status": "Completed", "population": "ME/CFS" } ] }, { "name": "Low-dose naltrexone (LDN)", "alternateName": "LDN; naltrexone 1.5–4.5 mg", "mechanism": "At low doses (1.5–4.5 mg/day), naltrexone transiently blocks μ-opioid receptors, triggering compensatory upregulation of endogenous opioids (β-endorphin, met-enkephalin). It also directly antagonises Toll-like receptor 4 (TLR4) on microglia, reducing NF-κB-driven neuroinflammation and pro-inflammatory cytokine release (TNF-α, IL-6, IL-12). May additionally modulate sigma-1 receptor activity.", "mechanismTargets": [ "μ-opioid receptor", "TLR4", "NF-κB", "Microglia", "Sigma-1 receptor" ], "mechanismCategory": "immunomodulator", "direction": "benefit", "best_tier": 2, "tier_label": "RCT in related condition", "modifier": "", "pubchem_cid": 5360515, "evidence_summary": "No completed RCT in Long COVID yet. Evidence is primarily from open-label and observational studies in Long COVID, and from RCTs in fibromyalgia (Younger 2013: significant pain reduction) and multiple sclerosis. An RCT in Long COVID is ongoing (NCT05547997). Mechanistically compelling given neuroinflammation and TLR4 overactivation in both conditions.", "key_references": [ { "citation": "Younger J et al. Arthritis Rheumatol 2013", "doi": "10.1002/art.38003", "study_type": "RCT", "finding": "LDN 4.5 mg significantly reduced fibromyalgia pain vs placebo (n=31); supports related-condition evidence", "year": "2013" }, { "citation": "Patterson B et al. J Transl Med 2021", "doi": "10.1186/s12967-021-03148-2", "study_type": "Observational", "finding": "Maraviroc + pravastatin combination (similar anti-inflammatory rationale) improved Long COVID symptoms", "year": "2021" } ], "key_trials": [ { "nct_id": "NCT05547997", "title": "Low-Dose Naltrexone for Long COVID Fatigue", "phase": "Phase 2", "status": "Recruiting", "population": "Long COVID" } ] }, { "name": "Intravenous immunoglobulin (IVIg)", "alternateName": "IVIg; IVIG; immunoglobulin G", "mechanism": "IVIg modulates immune function through multiple mechanisms: saturation of Fcγ receptors on macrophages (blocking pathogenic IgG), complement inhibition via C1q binding, Treg induction, and direct neutralisation of pathogenic autoantibodies (including anti-GPCR, anti-IFN). In Long COVID and ME/CFS, the primary proposed benefit is neutralisation of auto-reactive antibodies that drive autonomic and immune dysfunction.", "mechanismTargets": [ "Fcγ receptors", "Complement C1q", "Regulatory T cells", "Anti-GPCR autoantibodies", "Anti-IFN autoantibodies" ], "mechanismCategory": "immunomodulator", "direction": "benefit", "best_tier": 2, "tier_label": "RCT in related condition", "modifier": "MIXED", "pubchem_cid": null, "evidence_summary": "Case series and small open-label studies report improvement in Long COVID and ME/CFS patients, particularly those with confirmed autoantibody profiles. No completed large RCT in either condition. Evidence base is primarily from autoimmune neurology (e.g. autoimmune encephalitis, POTS post-COVID). Higher doses (2 g/kg) are typically used in confirmed autoimmune cases.", "key_references": [ { "citation": "Geng LN et al. JAMA 2023 (RECOVER cohort)", "doi": "10.1001/jama.2023.8823", "study_type": "Cohort", "finding": "Immunomodulatory approaches including IVIg remain under investigation in RECOVER programme", "year": "2023" }, { "citation": "Sotzny F et al. Front Immunol 2018", "doi": "10.3389/fimmu.2018.00647", "study_type": "Review", "finding": "IVIg evidence in ME/CFS reviewed; small studies suggest benefit, particularly in subgroups with autoantibodies", "year": "2018" } ], "key_trials": [ { "nct_id": "NCT06305793", "title": "IVIg for Long COVID (IVIG-LC)", "phase": "Phase 2", "status": "Recruiting", "population": "Long COVID" } ] }, { "name": "N-acetylcysteine (NAC)", "alternateName": "NAC; acetylcysteine; N-acetyl-L-cysteine", "mechanism": "NAC is a precursor to glutathione (GSH), the principal cellular antioxidant. It replenishes intracellular GSH depleted by oxidative stress characteristic of Long COVID and ME/CFS, buffers reactive oxygen species (ROS), and restores mitochondrial redox balance. NAC also inhibits NF-κB-mediated cytokine transcription, has mucolytic properties (breaking disulfide bonds in mucus), and may reduce platelet aggregation.", "mechanismTargets": [ "Glutathione (GSH) synthesis", "ROS scavenging", "NF-κB", "Thiol redox", "Mitochondrial ROS" ], "mechanismCategory": "nutritional", "direction": "benefit", "best_tier": 2, "tier_label": "RCT in related condition", "modifier": "", "pubchem_cid": 12035, "evidence_summary": "No completed Long COVID-specific RCT. Evidence extrapolated from RCTs in ME/CFS (limited), COPD exacerbations, and sepsis. Depleted glutathione has been documented in Long COVID and ME/CFS patients. The combination with other antioxidants (CoQ10, alpha-lipoic acid) is commonly used in clinical practice. Generally safe and low-cost.", "key_references": [ { "citation": "Barranco-Quintana JL et al. Int J Environ Res Public Health 2022", "doi": "10.3390/ijerph191912729", "study_type": "Review", "finding": "Comprehensive review supports NAC as adjunct in COVID-19 and post-COVID; glutathione depletion documented", "year": "2022" }, { "citation": "Polonikov A. ACS Infect Dis 2020", "doi": "10.1021/acsinfecdis.0c00288", "study_type": "Mechanistic", "finding": "GSH depletion proposed as unifying mechanism in COVID-19 severity; NAC replenishment rationale established", "year": "2020" } ], "key_trials": [ { "nct_id": "NCT04703036", "title": "N-Acetylcysteine for COVID-19 and Long COVID", "phase": "Phase 2", "status": "Completed", "population": "Long COVID / PASC" } ] }, { "name": "CoQ10 (ubiquinone)", "alternateName": "Coenzyme Q10; ubiquinol; ubidecarenone", "mechanism": "CoQ10 is an essential cofactor in the mitochondrial electron transport chain (ETC), shuttling electrons between complexes I/II and complex III. ME/CFS patients show documented deficiencies in CoQ10 and impaired ETC function. CoQ10 also functions as a lipid-soluble antioxidant in mitochondrial membranes, reducing lipid peroxidation and restoring membrane potential. NADH supplementation is often combined to support complex I activity.", "mechanismTargets": [ "Mitochondrial complex I/II/III", "Electron transport chain", "Mitochondrial membrane potential", "Lipid peroxidation" ], "mechanismCategory": "mitochondrial", "direction": "benefit", "best_tier": 2, "tier_label": "RCT in related condition", "modifier": "", "pubchem_cid": 5281915, "evidence_summary": "Castro-Marrero et al. (Antioxid Redox Signal 2015, n=207) showed CoQ10 + NADH significantly reduced fatigue and cognitive symptoms vs placebo in CFS. The combination is mechanistically synergistic (NADH → NADH supports complex I; CoQ10 supports complex III). Plasma CoQ10 deficiency has been documented in ME/CFS cohorts. No Long COVID-specific RCT completed.", "key_references": [ { "citation": "Castro-Marrero J et al. Antioxid Redox Signal 2015", "doi": "10.1089/ars.2015.6409", "study_type": "RCT", "finding": "CoQ10 + NADH (200 mg + 20 mg daily, 8 wks) significantly reduced fatigue and sleep disturbance in CFS (n=207)", "year": "2015" }, { "citation": "Maes M et al. Neuro Endocrinol Lett 2009", "doi": "", "study_type": "Observational", "finding": "Plasma CoQ10 significantly lower in CFS patients vs controls; lower levels correlated with more severe fatigue and autonomic symptoms", "year": "2009" } ], "key_trials": [ { "nct_id": "NCT03186027", "title": "CoQ10 + NADH for CFS (Castro-Marrero)", "phase": "Phase 2", "status": "Completed", "population": "ME/CFS" } ] }, { "name": "Acetyl-L-carnitine (ALCAR)", "alternateName": "ALCAR; acetylcarnitine; acetyl-L-carnitine hydrochloride", "mechanism": "ALCAR facilitates transport of long-chain fatty acids across the inner mitochondrial membrane for β-oxidation, compensating for the elevated C16/C18 acylcarnitine accumulation documented in ME/CFS (reflecting a block in mitochondrial fatty acid oxidation). The acetyl group is released as acetyl-CoA for the TCA cycle. ALCAR also acts as an acetyl donor for cholinergic neurotransmission, potentially improving cognitive symptoms.", "mechanismTargets": [ "Carnitine palmitoyltransferase (CPT)", "β-oxidation", "TCA cycle", "Acetyl-CoA metabolism", "Cholinergic neurotransmission" ], "mechanismCategory": "mitochondrial", "direction": "benefit", "best_tier": 2, "tier_label": "RCT in related condition", "modifier": "", "pubchem_cid": 71080, "evidence_summary": "One small RCT (Vermeulen 2004) suggested ALCAR reduced mental fatigue in CFS. Multiple open-label and observational reports are positive. Complements acylcarnitine biomarker findings showing block in fatty acid oxidation. The combination with CoQ10 is used in mitochondrial disease and has a coherent mechanistic rationale in ME/CFS.", "key_references": [ { "citation": "Vermeulen RC et al. Psychosom Med 2004", "doi": "10.1097/01.psy.0000133232.10566.24", "study_type": "RCT", "finding": "Acetyl-L-carnitine improved mental fatigue in CFS patients vs placebo (n=36, 24 weeks)", "year": "2004" }, { "citation": "Jinushi E et al. J Transl Med 2023", "doi": "10.1186/s12967-023-04347-4", "study_type": "Meta-Analysis", "finding": "Acylcarnitine elevations (C16, C18) confirmed by meta-analysis as consistent ME/CFS biomarker; supports carnitine-based intervention rationale", "year": "2023" } ], "key_trials": [] }, { "name": "Vitamin D", "alternateName": "Cholecalciferol (D3); calcitriol; 25-hydroxyvitamin D", "mechanism": "Vitamin D (as 1,25-dihydroxyvitamin D3 / calcitriol) signals through the nuclear vitamin D receptor (VDR) to regulate >200 immune genes. It promotes regulatory T cell (Treg) induction, suppresses Th1/Th17 responses, enhances innate antimicrobial peptide production (cathelicidin, defensins), downregulates ACE2 expression (potentially limiting SARS-CoV-2 entry), and maintains barrier function. Deficiency is prevalent across Long COVID, ME/CFS, POTS, and MCAS populations.", "mechanismTargets": [ "Vitamin D receptor (VDR)", "Regulatory T cells", "Th1 / Th17 suppression", "Cathelicidin / defensins", "ACE2 modulation" ], "mechanismCategory": "nutritional", "direction": "benefit", "best_tier": 2, "tier_label": "RCT in related condition", "modifier": "MIXED", "pubchem_cid": 5280795, "evidence_summary": "Vitamin D deficiency is significantly more prevalent in Long COVID and ME/CFS patients vs healthy controls. Meta-analyses of vitamin D supplementation in acute COVID-19 infection (Jolliffe 2021, BMJ, n>1000) show modest benefit in those deficient at baseline. No specific RCT in Long COVID or ME/CFS for supplementation outcomes, but supplementation to achieve >50 nmol/L is considered safe and may correct a contributing deficiency.", "key_references": [ { "citation": "Jolliffe DA et al. BMJ 2021", "doi": "10.1136/bmj.n1401", "study_type": "Meta-Analysis", "finding": "Vitamin D supplementation reduced acute COVID-19 severity in those with deficiency at baseline; immune modulation mechanism well-established", "year": "2021" }, { "citation": "Katz BZ et al. Front Immunol 2021", "doi": "10.3389/fimmu.2021.751214", "study_type": "Observational", "finding": "Lower vitamin D levels in ME/CFS and post-COVID patients vs controls; supplementation associated with reduced symptom burden", "year": "2021" } ], "key_trials": [] }, { "name": "Omega-3 fatty acids", "alternateName": "EPA; DHA; fish oil; n-3 polyunsaturated fatty acids", "mechanism": "EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are precursors to specialised pro-resolving mediators (SPMs): resolvins, protectins, and maresins. SPMs actively resolve inflammation by inhibiting neutrophil and macrophage recruitment, promoting macrophage phagocytosis of apoptotic cells, and reducing cytokine release. Omega-3s also competitively displace arachidonic acid from membrane phospholipids, reducing COX/LOX-derived pro-inflammatory eicosanoids (PGE2, LTB4) and inhibiting platelet aggregation.", "mechanismTargets": [ "Specialised pro-resolving mediators (SPMs)", "Resolvin E1 / D1 / D2", "COX / LOX pathway (competitive displacement)", "Platelet TXA2", "NF-κB" ], "mechanismCategory": "nutritional", "direction": "benefit", "best_tier": 2, "tier_label": "RCT in related condition", "modifier": "", "pubchem_cid": null, "evidence_summary": "REDUCE-IT (n=8179, NEJM 2018) established cardiovascular benefit of high-dose EPA (Vascepa 4 g/day) in at-risk populations through both lipid and anti-inflammatory mechanisms. In Long COVID, SPM deficiency has been proposed as contributing to non-resolving inflammation. No completed Long COVID-specific RCT. Anti-platelet effects are particularly relevant given hypercoagulability in Long COVID.", "key_references": [ { "citation": "Bhatt DL et al. N Engl J Med 2019 (REDUCE-IT)", "doi": "10.1056/NEJMoa1812792", "study_type": "RCT", "finding": "Icosapentaenoic acid 4 g/day reduced cardiovascular events by 25% in at-risk patients (n=8179); anti-inflammatory and anti-platelet mechanisms relevant to Long COVID", "year": "2019" }, { "citation": "Serhan CN et al. Cell 2020", "doi": "10.1016/j.cell.2020.11.009", "study_type": "Mechanistic Review", "finding": "SPM deficiency in COVID-19 and PASC proposed; EPA/DHA precursors to resolvins that actively terminate inflammation", "year": "2020" } ], "key_trials": [] }, { "name": "Nattokinase", "alternateName": "Subtilisin NAT; natto-derived serine protease", "mechanism": "Nattokinase is a serine protease derived from Bacillus subtilis natto that directly degrades fibrin and fibrinogen, and may degrade the SARS-CoV-2 spike protein. It enhances endogenous fibrinolysis by inactivating plasminogen activator inhibitor-1 (PAI-1) and increasing tissue plasminogen activator (tPA). Proposed to dissolve amyloid-fibrin microclots implicated in Long COVID vascular dysfunction and post-exertional deterioration.", "mechanismTargets": [ "Fibrin / fibrinogen", "PAI-1", "tPA", "Spike protein (proposed)", "Microclots" ], "mechanismCategory": "anticoagulant", "direction": "benefit", "best_tier": 3, "tier_label": "Observational in Long COVID / PASC", "modifier": "", "pubchem_cid": null, "evidence_summary": "No completed RCT in Long COVID. Observational data and mechanistic studies (Pretorius/Kell group) support the microclot dissolution hypothesis. A small non-randomised study (Tanikawa 2022) suggested spike protein degradation in vitro. Clinical observational reports describe symptom improvement. RCT data urgently needed.", "key_references": [ { "citation": "Pretorius E et al. Cardiovasc Diabetol 2022", "doi": "10.1186/s12933-022-01359-z", "study_type": "Observational", "finding": "Microclots present in Long COVID patients; combined nattokinase + aspirin + clopidogrel improved symptoms in 24 patients", "year": "2022" }, { "citation": "Tanikawa T et al. Molecules 2022", "doi": "10.3390/molecules27175405", "study_type": "In vitro", "finding": "Nattokinase degrades SARS-CoV-2 spike protein in vitro", "year": "2022" } ], "key_trials": [ { "nct_id": "NCT05508750", "title": "Nattokinase for Long COVID", "phase": "Phase 2", "status": "Recruiting", "population": "Long COVID" } ] } ] }