Researchers propose seven hallmarks for skeletal muscle health

An international team has published a new framework in Nature Metabolism that defines seven measurable hallmarks of skeletal muscle health. The model aims to improve biomarker discovery, clinical trials and precision treatments at a time when muscle loss is gaining attention in obesity care, aging and metabolic disease.

Why it matters: - Skeletal muscle makes up 40% to 50% of total body mass in non-obese individuals and helps regulate metabolism, amino acid storage and signaling across organs. - The new framework gives researchers and clinicians a shared model for studying muscle health, beyond measuring muscle size alone. - The authors say the approach could support earlier diagnosis, better trial endpoints and more precise therapies for aging, cancer cachexia, cardiovascular disease and metabolic disorders.

What happened: - An international group of muscle and metabolic biology researchers published "The Hallmarks of Skeletal Muscle Health" in Nature Metabolism on August 20, 2026. - The paper defines seven interdependent properties that govern muscle integrity, resilience and function across the lifespan. - The study was authored by Anna Vainshtein, Bert Blaauw, Katrien De Bock, Pura Muñoz-Cánoves, Eric N. Olson, Coen A. C. Ottenheijm, Erik A. Richter, Jorge L. Ruas, Laurent Schaffer, Bruce Spiegelman and Marco Sandri. - The collaboration spans academic and research institutes in Canada, Italy, Switzerland, Spain, Denmark, France and the United States.

The details: - The seven hallmarks are metabolism and bioenergetics, proteostasis, genomics, excitability, structure, regeneration and crosstalk. - Metabolism and bioenergetics refers to switching between carbohydrates and fats while maintaining mitochondrial quality and microvascular perfusion. - Proteostasis covers protein synthesis, folding fidelity and cleanup through autophagy-lysosome and ubiquitin-proteasome systems. - Genomics includes transcriptional programs, chromatin interactions and epigenetic memory that shape muscle cell identity and adaptive potential. - Excitability is the conversion of motor neuron signals into calcium release and contraction at the neuromuscular junction and triads. - Structure refers to the sarcomeric scaffold, costameres and extracellular matrix that transmit force and resist mechanical stress. - Regeneration depends on satellite cells and their niche to repair tissue after injury or wear and tear. - Crosstalk describes endocrine and paracrine signaling through myokines, metabokines and extracellular vesicles that connect muscle with the brain, liver, bone, adipose tissue and gut. - Dr. Anna Vainshtein, first author from Craft Science Inc., said skeletal muscle is "far more than an engine for movement" and described it as a metabolic and endocrine hub.

Between the lines: - The framework arrives as GLP-1 receptor agonists are widely used for weight management, raising concerns about lean muscle loss during weight loss and weight cycling. - It also lands as myostatin/activin blockade, gene therapies and anabolic interventions struggle with endpoints that separate muscle mass from muscle quality and function. - Dr. Marco Sandri of the University of Padova said current clinical assessments often detect muscle decline too late and that failure in one hallmark can destabilize the full system. - Sandri said next-generation therapies may need to combine molecular or pharmacological strategies with exercise and nutrition. - The paper frames muscle health as a systems problem, not a single-tissue problem, which could push future studies toward multimodal treatment designs.

What's next: - The authors want the framework to guide biomarker discovery and early diagnostic panels. - The model is also intended to improve clinical trial design by giving researchers better endpoints for muscle quality and function. - Future therapies may pair drugs with exercise and nutrition to preserve physical independence and metabolic health. - The full study is available online in Nature Metabolism.