Purpose Polyphenolic plant extracts have demonstrated anti-inflammatory and anti-catabolic effects in vitro, however their meaningful translation into humans remains elusive. Urolithin A (UA), a gut-derived metabolite of ellagitannins, has shown promise for improving muscle function and metabolic health in rodent models. This study aimed to explore the impact of UA on insulin and anabolic sensitivity in human skeletal muscle cells. Methods Primary human myogenic cultures were derived from skeletal muscle biopsies of eight healthy adults. After differentiation, myotubes were treated with 0.002, 1 and 50 mu M UA or vehicle for 24 h. Cell viability was assessed using a resazurin assay. Basal and insulin-stimulated glucose uptake was measured using tritiated deoxy-D-glucose, whilst amino acid-stimulated protein synthesis was estimated using the surface sensing of translation (SuNSET) technique. Expression of myostatin and glucose transporters was quantified via real-time PCR. Results UA treatment at