Effects of Cacao Flavonoids in Long COVID-19 Patients with Chronic Fatigue: FLALOC, a Placebo-Controlled Randomized Clinical Trial

Abstract:

Background: In the context of long COVID, persistent fatigue is among the most prevalent symptoms that can develop after SARS-CoV-2 infection. Mitochondrial myopathy and endothelial dysfunction, which are triggers of inflammation, have emerged as prominent causes of long COVID-induced fatigue. Interestingly, the intake of flavanols, particularly (−)-epicatechin (EC), has been associated with the positive modulation of endothelial and mitochondrial structure and function.
Methods: In this work, we conducted a randomized, double-blind, placebo-controlled clinical trial to determine whether an EC-enriched supplement (ECES) improves plasma markers of inflammation, endothelial structure, and fatigue-related endpoints in patients with long COVID-19.
Results: The study included 46 subjects (mean age 52 years) who were instructed to consume two capsules/day for 90 days of either ECES (n = 23) or placebo (n = 23). Endpoints assessed included mean changes in plasma inflammatory markers (IL-1β, IL-6, and TNF-α) and endothelial dysfunction markers (syndecan-1), handgrip strength, fatigue scale, and quality of life (QoL). The results showed significant improvements in the ECES group for inflammatory markers, syndecan-1, and fatigue compared with the placebo group.
Conclusions: The results yield intriguing positive findings for EC and open a new avenue for treating long COVID.
Source: Munguía L, Silva S, Villarreal F, Nájera N, Ceballos G. Effects of Cacao Flavonoids in Long COVID-19 Patients with Chronic Fatigue: FLALOC, a Placebo-Controlled Randomized Clinical Trial. Journal of Clinical Medicine. 2026; 15(4):1468. https://doi.org/10.3390/jcm15041468 https://www.mdpi.com/2077-0383/15/4/1468 (Full text)

Potential application of brain-gut axis-based treatments in Long COVID and ME/CFS: a case-based systematic review

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID share clinical features including persistent fatigue, post-exertional malaise (PEM), and gastrointestinal (GI) dysfunction. Growing evidence implicates brain-gut axis dysregulation, characterized by dysbiosis, neuroinflammation within the central nervous system (CNS), increased intestinal permeability, and microbial translocation in their pathophysiology. However, therapeutic strategies targeting these pathways remain poorly defined.

Methods: We report a case of post-COVID ME/CFS successfully treated with electroacupuncture (EA)-based deep peroneal nerve stimulation which was employed to potentiate the vagal reflex. Fatigue trajectories were assessed using the Multidimensional Fatigue Inventory over 12 weeks. Based on the case, a systematic review of randomized controlled trials (RCTs) evaluating brain-gut axis-modulating interventions in ME/CFS or Long COVID was conducted.

Results: The patient exhibited a significant reduction in total fatigue, with early improvements in motivation and mental fatigue, and delayed improvement in physical fatigue following transient systemic symptom flares. Across included RCTs (n = 8, 790 participants), four investigated gut microbiome-modulating therapies and four employed nerve stimulation. Synbiotic and herbal interventions demonstrated benefits for fatigue or PEM, accompanied by alterations in specific bacterial populations or CNS metabolisms. Regarding nerve stimulation, transcranial direct current stimulation (tDCS) combined with exercise program improved fatigue, whereas standalone tDCS, auricular or peripheral TENS showed limited efficacy.

Conclusion: Brain-gut axis-based interventions may alleviate fatigue in ME/CFS and Long COVID by potentially modulating neuroinflammation, restoring microbiome balance, and improving epithelial barrier function. EA-based vagal stimulation represents a feasible option for patients with severe or treatment-resistant symptoms. Larger mechanistic studies and rigorously designed RCTs are needed to establish therapeutic targets and optimize intervention strategies.

Source: Kim DY, Youn J, Kang N, Cho SI, Ha IH. Potential application of brain-gut axis-based treatments in Long COVID and ME/CFS: a case-based systematic review. J Transl Med. 2026 Feb 10. doi: 10.1186/s12967-026-07807-w. Epub ahead of print. PMID: 41668172. https://link.springer.com/article/10.1186/s12967-026-07807-w (Full text available as PDF file)

Re-analysis: 200 treatments by 4000 Long Covid/ME patients

I ranked 200+ treatments by effect scores and got a new Top 5

In 2023, a survey was run among 3,925 ME/CFS and Long Covid patients called TREATME. It asked patients which treatments they have tried and how they responded to it. It is by far the biggest survey of its kind. I am really grateful to Martha Eckey, a PharmD and patient herself, for collecting the data and to the Open Medicine Foundation for having helped her to analyze and publish it.

At the time I wasn’t very interested in the results, but I’ve since come to appreciate the severity of publication biases. Those retrospective “we treated x patients with treatment Y without blinding and without controls” only get published if there are positive results! This survey, on the other hand, would have been published regardless of any individual treatment results, making it significantly more trustworthy (although not as good as well-designed RCTs).

Read the rest of this article here: https://viralpersistence.substack.com/p/re-analyzing-the-treatme-survey?triedRedirect=true

Testing the Feasibility of a Self-Help Intervention That Includes Lymphatic Drainage to Reduce Fatigue-Related Symptoms Among Patients with Long COVID in General Practice: Experiences from Our Randomized Controlled Trial (RCT)

Abstract:

Introduction: Long COVID-related fatigue affects a large number of people across the world, with increasing numbers of people experiencing long-term disability as a consequence. We tested the feasibility of a self-help version of a manual osteopathic approach initially developed for people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) to treat people with long COVID-related fatigue.

Methods: Our feasibility study assessed recruitment into a 1:1 randomized controlled trial (RCT) to receive (i) self-help intervention (self-massage, mobility, flexibility, and breathing exercises, and alternating cold and warm packs to the top of the spine) or (ii) wait-list control group. Follow-up was assessed by online surveys at 3 and 6 months (indicating retention). Verbal feedback was obtained from participants.

Results: Of the 138 eligible survey participants, 126 (90.6%) agreed to participate in two RCTs, achieving the required sample size of 100. Follow-up rates of 79.3% and 59.4% were achieved at 3 and 6 months, respectively. Improvements in Chalder Fatigue Questionnaire (CFQ) scores were observed in both groups between 0 and 3 months (- 4.6 and – 2.9, respectively), to a greater degree in the intervention group (p = 0.01). Feedback showed a cohort keen to engage with the intervention, although some found the intervention onerous at times.

Conclusions: We have reported the results of a feasibility study examining a potentially beneficial intervention for people with long COVID. There were indications of benefit in a patient group with often intractable symptoms. Based on this feasibility study, we believe that the low-cost self-help intervention in isolation could help support fatigue reduction in some people. This has implications for the treatment of both long COVID and ME/CFS.

Source: Riste L, Perrin R, Mulholland T, Hann M, McDonald O, Heald A. Testing the Feasibility of a Self-Help Intervention That Includes Lymphatic Drainage to Reduce Fatigue-Related Symptoms Among Patients with Long COVID in General Practice: Experiences from Our Randomized Controlled Trial (RCT). Infect Dis Ther. 2025 Dec 24. doi: 10.1007/s40121-025-01287-z. Epub ahead of print. PMID: 41442105. https://link.springer.com/article/10.1007/s40121-025-01287-z (Full text)

Long COVID: a long road ahead

Abstract:

The SARS-CoV-2 pandemic caused an estimated 400 million people worldwide to experience Long COVID and post-COVID complications leading to significant chronic illness and disability with its devastating physical, societal and economic consequences. Since post-acute infectious syndromes have not been given adequate consideration prior to the pandemic, many millions of people with Long COVID worldwide have been left disabled as currently available therapies are largely symptomatic and only partially effective.

A case of a previously healthy woman with Long COVID and post-COVID autonomic dysfunction and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is presented here from the perspective of a physician-patient relationship and a broader context of medical care and public health. Immunologic and autonomic mechanistic factors and therapies as these relate to Long COVID are highlighted.

Complexities and issues pertaining to patient care, public health and education of neurologists and other specialists regarding Long COVID, dysautonomia and ME/CFS diagnosis and treatment are discussed, in conjunction with the need to develop and diversify effective therapies for people living with these highly disabling conditions.

Source: Blitshteyn S. Long COVID: a long road ahead. Oxf Open Immunol. 2025 Dec 13;6(1):iqaf010. doi: 10.1093/oxfimm/iqaf010. PMID: 41426345; PMCID: PMC12718103. https://pmc.ncbi.nlm.nih.gov/articles/PMC12718103/ Full text)

Lingering echoes of SARS-CoV-2: mechanistic insights and management of long COVID syndrome

Abstract:

Throughout the world-wide COVID-19 pandemic, there has arisen a significant and a sustained public-health issue, whereby a significant proportion of individuals report persistent symptoms, well beyond the acute period of infection. The non-united array of chronic, multisystemic events, such as fatigue, cognitive deficit, respiratory dysfunction, cardiovascular abnormalities, and neuropsychiatric disorders characterize this sequela, which is referred to as LCS. LCS is much more than the starting viral insult, as it causes long-term complications that impact various organ systems.

The current review questions the pathophysiological mechanisms of LCS, including scrutinizing the importance of the dysregulation of immunity, the persistence of viral reservoirs, endothelial dysfunction, autonomic imbalance, and mitochondrial injury. We highlight the heterogeneity of the syndrome and the associated diagnostic and treatment difficulties. In addition, we stress the urgency of powerful biomarkers that will be used to diagnose LCS as early as possible and monitor it over time. Present treatment strategies, including pharmacologic therapy (immunomodulators, anticoagulants, antiviral medications, etc.) and non-pharmacologic treatment (rehabilitative programs, etc.) are discussed against the backdrop of recent clinical findings.

This review incorporates the recent literature and presents a review of potential treatment options that alleviate symptoms and improve the quality of life of LCS patients. Finally, this integrated synthesis can be used by both clinicians and researchers to gain practical information on the diagnosis, treatment, and future treatment directions of LCS.

Source: Yadav JP, Yadav S, Dubey NK, Yadav IP, Pathak P, Verma A. Lingering echoes of SARS-CoV-2: mechanistic insights and management of long COVID syndrome. Inflammopharmacology. 2025 Nov 30. doi: 10.1007/s10787-025-02062-9. Epub ahead of print. PMID: 41318861. https://pubmed.ncbi.nlm.nih.gov/41318861/

Integrated immune, hormonal, and transcriptomic profiling reveals sex-specific dysregulation in long COVID patients with ME/CFS

Abstract:

Long COVID (LC) manifests with sex-specific differences, particularly in those with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Our study reveals that female LC patients (LCF) with ME/CFS show a shift toward myelopoiesis, reduced lymphocytes, increased neutrophils/monocytes, and depleted regulatory T cells-suggesting persistent immune activation. Elevated CD71+ erythroid cells and disrupted erythropoiesis contribute to fatigue and tissue damage in LCF.

Cytokine profiling indicates a stronger pro-inflammatory response in LCF compared to males (LCM), along with markers of gut barrier dysfunction. Hormonal analysis shows reduced testosterone in LCF and estradiol in LCM. Transcriptomic data reveal neuroinflammatory signatures in LCF, potentially explaining cognitive symptoms. We also identify biomarkers that distinguish LCF from LCM and correlate with sex-specific clinical symptoms.

Overall, LC with ME/CFS is characterized by sex-specific immune, hormonal, and transcriptional alterations, with females exhibiting more severe inflammation. These insights underscore the need for sex-tailored interventions, including consideration of hormone replacement therapy.

Source: Shahbaz S, Osman M, Syed H, Mason A, Rosychuk RJ, Cohen Tervaert JW, Elahi S. Integrated immune, hormonal, and transcriptomic profiling reveals sex-specific dysregulation in long COVID patients with ME/CFS. Cell Rep Med. 2025 Nov 7:102449. doi: 10.1016/j.xcrm.2025.102449. Epub ahead of print. PMID: 41205594. https://www.cell.com/cell-reports-medicine/fulltext/S2666-3791(25)00522-1 (Full text)

A Perspective on the Role of Metformin in Treating Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID (LC) are increasingly recognized as debilitating postinfectious conditions that impact both individuals and society. Recent research highlights the potential of metformin, an antidiabetic agent, as a treatment for these syndromes by targeting their underlying mechanisms. This review assesses the effectiveness of metformin in ME/CFS and LC, which involve complex dysfunctions related to cytokines, glycolysis, ATP generation, oxidative stress, gastrointestinal microbiomes, and vascular endothelial function.

Metformin, traditionally known for its antihyperglycemic properties may offer broader therapeutic benefits by influencing these pathological pathways. It works by inhibiting complexes I and IV of the electron transport chain, which reduces the strain on malfunctioning complex V and decreases the production of harmful free radicals. Additionally, metformin’s impact on mTOR signaling could improve energy metabolism in ME/CFS and LC by downregulating an overactive but underperforming protein, thereby alleviating symptoms. Beyond the impact on cellular metabolism, metformin has shown to have anti-inflammatory, vascular, gastrointestinal, neuroprotective and epigenetic effects.

We explore this impact of metformin and the potential role it could play to help people with ME/CFS. While metformin shows promise, it is unlikely to be a stand-alone solution. Instead, it may be part of a broader treatment strategy that includes other therapies targeting neurocognitive and autonomic impairments.

Source: David Fineberg, Alain Moreau, Elena K. Schneider-Futschik, and Christopher W. Armstrong. A Perspective on the Role of Metformin in Treating Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID. ACS Pharmacology & Translational Science Article ASAP. DOI: 10.1021/acsptsci.5c00229 https://pubs.acs.org/doi/full/10.1021/acsptsci.5c00229 (Full text)

Disruptions in serotonin- and kynurenine pathway metabolism in post-COVID: biomarkers and treatment

Introduction:

This opinion article attempts to connect knowledge about post-COVID syndrome (PCS) gained in neuropsychiatry and immunology. It discusses some misunderstandings about PCS in light of the interplay between the serotonergic system and the kynurenine pathway (KP). From a new perspective, potential biomarkers for further research and therapeutic targets are identified.

Due to the severity and extent of PCS, researchers are urgently searching for its causes and treatments. For neurocognitive and autonomic nervous system problems such as present in PCS, it is common to encounter dysregulated neurotransmitter systems. Among the neurotransmitters, serotonin plays a special role in the immune system and in regulating inflammatory responses by central and peripheral mechanisms (). Serotonin—also known as 5-hydroxytryptamine (5-HT)—is a neurotransmitter with a stimulating effect that influences memory, mood, self-confidence, sleep, emotion, orgasm and eating ().

Serotonin not only binds to serotonergic receptors on neurons, but also to receptors on immune cells (). Many studies indicate that serotonin and its receptors, especially 5-HT3 receptors (one of the serotonin receptors), are involved in the pathogenesis of chronic inflammatory conditions (). Therapeutic applications of 5-HT3 receptor antagonists for instance have been reported in rheumatoid arthritis (). An essential amino acid in the serotonin system and also in the KP is tryptophan, a precursor of both serotonin and kynurenine (see Figure 1) and part of a regular diet (). The KP is a pathway creating an important energy factor and is modulated in conditions as infection and stress (). Kynurenine regulates the balance between two types of thymus cells (T-cells): regulatory T-cells (Treg-cells), and subsets of T helper 17 cells (Th17 cells) that produce cytokines and have a signaling function ().

In this opinion article I address the question whether disruptions in the serotonin- and kynurenine pathway metabolism lead to new biomarkers and treatment in PCS.

Source: Rus CP. Disruptions in serotonin- and kynurenine pathway metabolism in post-COVID: biomarkers and treatment. Front Neurol. 2025 Feb 13;16:1532383. doi: 10.3389/fneur.2025.1532383. PMID: 40027165; PMCID: PMC11869386. https://pmc.ncbi.nlm.nih.gov/articles/PMC11869386/ (Full text)

How I treat my patients with Myalgic Encephalomyelitis, Chronic Fatigue Syndrome (ME/CVS), fibromyalgia or “long COVID”

Abstract:

Common to Myalgic encephalomyelitis, chronic fatigue syndrome and so-called long Covid is the panoply of complaints, with Post Exertional Malaise (PEM) as the most typical symptom. Added to that are permanent feeling of fatigue, decreased capacity to concentrate, so-called brain fog, non restorative sleep, diffuse pain, and – in case of long Covid – respiratory distress.

Several recent studies have confirmed my original hypothesis that poor metabolism and energy production by the mitochondria are responsible for the majority of these phenomena. I have suggested that inhibition of Pyruvate dehydrogenase (Pdh) activity is the major reason for this. Pdh inhibition is probably caused by the excess of the phosphatase: Pyruvate Dehydrogenase Kinase (PDK). The latter results from “Systemic Immune Disorder” (what I called “SID”) and inflammation.

Based on this hypothesis I have applied oral and infusion treatment modalities which were successful in approximately 80% of 130 consecutive patients. The pivotal substances are sodium dichloroacetate, that reduces PDK, Meldonium, that facilitates intracellular glucose metabolism, and low dose Nalexone, that optimises the function of microglia.

Source: Comhaire F. How I treat my patients with Myalgic Encephalomyelitis, Chronic Fatigue Syndrome (ME/CVS),
Fibromyalgia or “long COVID”. J Clin Images Med Case Rep. 2025; 6(3): 3508. https://jcimcr.org/pdfs/JCIMCR-v6-3508.pdf (Full text)