SS-31 (Elamipretide) is a synthetic tetrapeptide that selectively targets the inner mitochondrial membrane by binding to cardiolipin — a phospholipid essential for maintaining the structure and function of the electron transport chain. By stabilizing cardiolipin and preventing its peroxidation, SS-31 protects mitochondrial cristae architecture, restores electron transport chain efficiency, and reduces reactive oxygen species generation. Research has demonstrated cytoprotective and cardioprotective effects in models of ischemia-reperfusion injury, heart failure, neurodegenerative disease, and aging-associated mitochondrial decline.