Myoblast migration represents a key step in muscle regeneration following microdamage after exercise (1). Myosatellite cell fusion with the damaged myofibre and subsequent differentiation pilots muscle remodelling (2). While increased production of Reactive Oxygen Species (ROS) is crucial in exercise-induced muscle damage (3). In line with this, antioxidant supplementation, such as the polyphenol resveratrol, may suppress skeletal muscle damage and improve anti-oxidant capacity (4). However, ROS is also crucial for exercise-mediated adaptation and repair (5). The way at which ROS and/or resveratrol modulate myoblast function in muscle repair remains unclear. Here, we explored the individual and combined effect of different concentrations of resveratrol (RS; 10-20-40-60 μM) and hydrogen peroxide (H2O2; 2-1 mM, 800-500-100-50-10μM) on non-differentiated (myoblasts) and differentiated (myotubes) mouse skeletal muscle-derived cells (C2C12). The impact of RS on myoblasts regenerative capacity was tested by assessing cell morphology, proliferation (MTS assay), migration (wound healing), sprouts formation (spheroids assay) and myotube formation and/or shrinking. In myoblasts, we tested the effect of RS plus H2O2 on cell migration. In 8-days differentiated myotubes we studied the impact of RS plus H2O2 on the oxidative capacity [succinate dehydrogenase (SDH) activity] and myosin ATPase activity and composition (total and type1-myosin). Data analysed by ANOVA in five replicates. The effect of RS on cell mitosis (24-48h) and proliferation (72h) was dose dependent; RS 10-20μM did not show significant effects, but at higher doses (40-60μM) it impaired both cell processes (p<0.01). RS 10-20μM enhanced (p=0.03) migration and the formation of myoblast sprouts, but not cell fusion. RS 40-60μM almost blocked myoblast regenerative capacity. In parallel, low doses of H2O2(10-500μM) enhanced motility with the highest efficiency at 100μM, while higher doses showed damaging effects. Notably, 24h of RS pre-conditioning (10-20μM) prevented the deleterious effects of H2O2(1mM) and further enhanced cell migration induced by H2O2100μM. Evidence suggests that RS may increase fibre oxidative metabolism (4). Surprisingly, we did not find any effect of RS on myotube oxidative capacity (SDH), while we found a reduction (p<0.01) in myosin type1-ATPase activity and increased total myosin ATPase content. Finally, H2O2 (1mM) induced a reduction (p<0.01) in total and myosin type1 ATPase activity, that was prevented by RS in a dose-dependent manner. In conclusion, our data support the notion that low concentrations of ROS enhance myoblast regenerative capacity while it is impaired at high concentrations. High doses of anti-oxidants may also impair regenerative capacity, while low doses may abolish the detrimental impact of high concentrations of ROS on muscle regeneration.