SS-31

SS-31, also known as elamipretide, is a synthetic tetrapeptide that interacts with cardiolipin in the inner mitochondrial membrane. In 2025, the US FDA granted accelerated approval to Forzinity (elamipretide) for a specific use related to muscle strength in patients with Barth syndrome who weigh at least 30 kg. This decision is not a general approval for other mitochondrial, metabolic or ageing-related indications.

Mitochondria are often described as the cell’s power plants because they produce most of the adenosine triphosphate (ATP) required for biological processes. When mitochondrial function is impaired, cells may become less efficient, oxidative stress can increase and normal tissue function can be affected. Researchers therefore study mitochondrial biology not only in rare genetic diseases but also in cardiovascular, neurodegenerative, muscular and ageing-related models.

One major area of SS-31 research is cellular metabolism. Mitochondria determine how efficiently cells produce and use energy, linking their function directly to ATP synthesis and metabolic homeostasis. Experimental work suggests that supporting mitochondrial function may reduce oxidative stress and improve energy-production efficiency. This is why SS-31 has received considerable attention in metabolism and mitochondrial-biology research.

The cardiovascular system is another focus because heart muscle has a continuous and exceptionally high energy requirement. Animal studies have reported reduced mitochondrial injury after ischaemia and changes in cardiac energetics. Clinical research has also examined elamipretide in conditions involving mitochondrial dysfunction. Skeletal-muscle function and exercise capacity form a related research area, as muscle performance depends on continuous ATP production. Researchers are investigating whether mitochondrial support can influence muscle biology, exercise tolerance and recovery, but these questions still require additional clinical evidence.

Studies in aged animals have reported reductions in mitochondrial oxidative stress and improvements in the ability of mitochondria to produce ATP after SS-31 exposure.

Other experimental models have shown improved energetic efficiency in heart cells and less tissue injury after ischaemia and reperfusion. Skeletal-muscle studies have reported better mitochondrial function and exercise tolerance in some models. Clinical research in Barth syndrome contributed to the FDA decision on elamipretide for this specific rare mitochondrial disorder.

SS-31 is also studied in neurology and healthy-ageing research. Brain cells, like cardiac muscle, require large amounts of energy and depend on effective mitochondrial function. Researchers are asking whether mitochondrial protection might improve cellular resilience to oxidative stress and clarify biological processes associated with ageing. Much of this work remains ongoing.

The biological mechanism of elamipretide and its Barth syndrome indication are important in mitochondrial medicine, but clinical results in other conditions have not been consistent. In the MMPOWER-3 trial, primary walking and fatigue outcomes did not improve versus placebo after 24 weeks. Other proposed applications should therefore not be described as clinically established.