SS-31, also known as elamipretide, is a synthetic tetrapeptide designed to target and protect mitochondria, the energy-producing organelles in cells. It selectively localizes to the inner mitochondrial membrane, where it interacts with cardiolipin, a phospholipid vital for mitochondrial function. SS-31 has antioxidant properties and helps improve mitochondrial efficiency, reduce oxidative stress, and support cellular energy production. It is being studied for potential therapeutic effects in conditions involving mitochondrial dysfunction, such as age-related diseases, neurodegenerative disorders, and cardiovascular diseases.