BACKGROUND: Endoplasmic reticulum stress (ERS) plays a critical role in skeletal muscle physiology and pathology, though the precise mechanisms remain unclear. Salubrinal, a selective inhibitor of eIF2α dephosphorylation, has been shown as a potential therapeutic agent for various conditions, but its effects on sarcopenia are not well understood. This study investigated the protective effects of salubrinal against H(2)O(2)-induced muscle cell injury and its impact on the eIF2α/ATF4 signaling pathway. METHODS: Gastrocnemius muscle samples from aged mice were used and cultured C2C12 myotubes were also used to explore the effects of Salubrinal through Western blotting, immunofluorescence, and apoptosis assays. RESULTS: Our results demonstrated that H(2)O(2) treatment induced significant muscle cell damage, evidenced by reduced MHC1 expression and increased apoptosis. Salubrinal, in a concentration-dependent manner, mitigated these effects, preserving MHC1 expression and reducing apoptosis. Furthermore, salubrinal enhanced the expression of p-eIF2α and ATF4, suggesting that its protective effects are mediated through the eIF2α/ATF4 pathway. CONCLUSION: These findings highlight salubrinal's potential as a therapeutic agent for muscle wasting conditions, particularly those related to oxidative stress and ERS.