SS-31 (Elamipretide), with the molecular formula C32H49N9O5, is a synthetic tetrapeptide and selective mitochondria-targeting agent designed to address dysfunction in cellular energy production. Composed of the sequence D-Arg-Dmt-Lys-Phe-NH2, it exhibits high affinity for cardiolipin, a key phospholipid in the inner mitochondrial membrane, where it binds to stabilize cristae architecture and optimize electron transport chain function. This interaction mitigates reactive oxygen species (ROS) production, preserves mitochondrial integrity, and boosts adenosine triphosphate (ATP) synthesis, thereby counteracting oxidative stress and enhancing overall bioenergetics in stressed cells. These properties position SS-31 as a promising therapeutic for conditions rooted in mitochondrial impairment, such as Barth syndrome—a rare genetic disorder characterized by cardiomyopathy and skeletal myopathy—where it has received FDA approval to improve muscle strength and endurance. Preclinical models have further demonstrated its efficacy in ameliorating heart failure, neurodegeneration, ischemia-reperfusion injury, metabolic syndromes, and muscle atrophy by reducing inflammation and restoring mitochondrial plasticity. In clinical trials, including PROGRESS-HF and MMPOWER-3, SS-31 has shown improvements in cardiac function and exercise tolerance, with a favorable safety profile marked primarily by mild injection-site reactions. Emerging evidence also suggests potential in age-related mitochondrial decline, promoting cellular repair and longevity through sustained energy homeostasis.