Elamipretide is a prescription medicine used to improve muscle strength in adults and children (weighing at least 30 kg) with Barth syndrome, a rare genetic disorder that affects the heart, muscles, and immune system. It works as a mitochondrial cardiolipin binder that targets the inner mitochondrial membrane to stabilize cardiolipin, a lipid essential for energy production, thereby improving mitochondrial structure and function. It is given as a once-daily subcutaneous injection at the same time each day, typically in the abdomen or thigh. The most common side effects are injection site reactions, such as redness, pain, itching, bruising, or swelling