Updated 25/05/2026
A preclinical study led by investigators at Mass General Brigham and University Medical Center Hamburg-Eppendorf (UKE) has identified a potential mechanism by which exercise improves neurological outcomes in multiple sclerosis (MS), centring on the exercise-derived hormone irisin. The research, conducted in a mouse model of MS, provides mechanistic insight into why physical activity remains one of the most accessible interventions for MS symptom management.
Exercise and MS: Closing the Mechanistic Gap
Physical activity has long been recognised as a non-pharmacological intervention that can benefit MS patients, however, the biological pathways connecting exercise to neurological benefit have remained incompletely understood. The Mass General Brigham and UKE collaboration targeted this gap by examining irisin, a myokine—a signalling molecule released by contracting muscle—in the context of experimental autoimmune encephalomyelitis (EAE), a murine model commonly used to study MS pathophysiology.
Irisin, first characterised in Nature Medicine as a product of muscle-derived FNDC5 cleavage, has since emerged as a pleiotropic hormone with functions extending beyond metabolic regulation. The hormone crosses the blood-brain barrier and interacts with FGFR1c (fibroblast growth factor receptor 1c) on central nervous system cells, positioning it as a candidate mediator of exercise’s neuroprotective effects.
Preclinical Evidence and Oligodendrocyte Preservation
According to the Mass General Brigham and UKE research team, in their EAE model, elevated irisin levels corresponded with reduced demyelination and improved neurological function scores compared to controls with lower circulating irisin. The hormone’s protective effect appeared most pronounced in preserving oligodendrocyte populations, the cells responsible for generating and maintaining myelin sheaths around axons.
The Mass General Brigham and UKE study demonstrated that irisin reduced the infiltration of pro-inflammatory T cells and macrophages into the spinal cord, the primary site of EAE pathology. Furthermore, irisin application in vitro suppressed the production of tumour necrosis factor-alpha (TNF-α) and interleukin-17 (IL-17) by activated immune cells—key cytokines driving MS neuroinflammation.
For context on MS disease mechanisms and existing treatment approaches, readers may find related coverage in our Clinical Updates section, which tracks novel MS therapeutics and guideline changes.
From Bench to Bedside: Clinical Translation Challenges
While preclinical data are encouraging, translation of irisin-based therapeutics to clinical practice faces several barriers. First, irisin’s short circulating half-life and potential immunogenicity as a recombinant protein necessitate formulation advances—liposomal delivery, PEGylation, or engineered irisin analogues may be required to achieve sustained CNS exposure. Second, the optimal dose, frequency, and duration of irisin administration in humans remain unknown and will require carefully designed Phase I/II trials.
Third, and most broadly, the current standard of care for MS—disease-modifying therapies (DMTs) including interferons, monoclonal antibodies, and small-molecule inhibitors—already provide substantial disease control in many patients. Any future irisin-based treatment would need to demonstrate superiority, equivalence with improved tolerability, or synergy with existing DMTs to secure a clinical niche. The U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) will require Phase III efficacy and safety data in human MS cohorts before approval consideration.
This research underscores why structured exercise programmes remain a cornerstone of MS management. Rather than waiting for irisin-based drugs, current clinical guidance emphasises regular aerobic and resistance activity tailored to individual disability levels. For readers interested in evidence-based MS management strategies, our Health Policy section covers relevant clinical guidelines and access issues.
Key takeaways
- Irisin, an exercise-derived myokine, demonstrated neuroprotective effects in a preclinical MS model by suppressing neuroinflammation and preserving oligodendrocyte function, according to Mass General Brigham and UKE researchers.
- The hormone’s mechanism involves FGFR1c receptor activation on central nervous system cells, reducing pro-inflammatory cytokine production and immune cell infiltration.
- Clinical translation remains in early stages; formulation challenges, optimal dosing, and comparison with existing disease-modifying therapies must be resolved before human trials.
- Meanwhile, structured exercise remains an accessible, evidence-based complementary strategy for MS symptom management and disease progression slowing.
Frequently asked questions
What is irisin, and where does it come from?
Irisin is a myokine—a signalling hormone produced and released by contracting skeletal muscle during physical activity. First described in Nature Medicine in 2012, irisin is generated through cleavage of the precursor protein FNDC5 and circulates in the bloodstream, crossing the blood-brain barrier to affect neurological function. Levels increase significantly during aerobic and resistance exercise.
Why might irisin be relevant to multiple sclerosis treatment?
MS is characterised by myelin loss and oligodendrocyte destruction driven by autoimmune inflammation. The Mass General Brigham and UKE research shows irisin suppresses pro-inflammatory cytokines (TNF-α, IL-17) and protects myelin-producing cells in preclinical models. This provides a molecular explanation for why exercise improves MS symptoms and suggests irisin could be a therapeutic target to enhance neuroprotection.
When might irisin-based drugs become available to MS patients?
Clinical translation is likely several years away. Researchers must first optimise irisin formulation to extend its short half-life, then conduct Phase I safety studies, followed by Phase II efficacy trials in MS cohorts. The FDA and EMA will require robust Phase III data before approval. Current MS disease-modifying therapies remain the standard of care; exercise continues to be recommended alongside pharmacological treatments.
The Mass General Brigham and UKE findings align with a broader shift in neurology towards understanding exercise-derived signalling molecules as therapeutic targets. Future research will likely focus on identifying synthetic irisin mimetics or strategies to amplify endogenous irisin production in MS patients, potentially combining such approaches with existing immunomodulatory therapies. Until clinical trials begin, the message for people living with MS remains consistent: structured, regular physical activity supported by evidence-based medical care remains the most accessible neuroprotective strategy available today.
Source: Exercise hormone irisin could offer neuroprotective effects in multiple sclerosis
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