SS-31
SS-31 is a small synthetic peptide designed to reach the inner membrane of mitochondria—the structures responsible for producing much of a cell’s usable energy. Researchers study whether it can support mitochondrial function, protect membrane structure, and help cells respond to stress.
SS-31 AT A GLANCE
WHAT IS SS-31?
SS-31 is a laboratory-made peptide containing only four amino acids. It belongs to a group known as Szeto-Schiller peptides and is also called elamipretide, MTP-131, or Bendavia in scientific literature.
Its structure allows it to reach mitochondria and collect near their inner membrane. This membrane contains the proteins responsible for producing cellular energy and a specialized fat called cardiolipin that helps organize and support the entire energy-producing system.
HOW DOES SS-31 WORK?
SS-31 binds to cardiolipin within the inner mitochondrial membrane. Cardiolipin helps maintain the curved membrane structure needed for energy production and supports the protein complexes that transfer electrons and produce ATP—the form of energy cells can use.
When cardiolipin becomes damaged or poorly organized, mitochondria may produce energy less efficiently and release more reactive oxygen molecules. By interacting with cardiolipin and changing properties of the surrounding membrane, SS-31 may help improve mitochondrial structure and function. Researchers are still examining the exact actions involved, and its effects may differ depending on the disease or type of mitochondrial damage being studied.
Areas of Research
SS-31 research explores whether protecting the inner mitochondrial membrane can improve the way cells produce energy and respond to disease, injury, and aging.
MITOCHONDRIAL FUNCTION
Examining membrane structure, electron transport, oxygen use, and the production of ATP inside mitochondria.
MUSCLE STRENGTH AND ENDURANCE
Studying whether improved mitochondrial function affects muscle energy, fatigue, exercise tolerance, and physical performance.
OXIDATIVE STRESS
Exploring whether SS-31 can reduce the inefficient electron activity that contributes to excessive production of damaging reactive oxygen molecules.
HEART, EYE, AND AGE-RELATED HEALTH
Investigating mitochondrial dysfunction in heart failure, retinal disease, kidney injury, neurological conditions, and biological changes associated with aging.
Research Highlights
Research involving Barth syndrome has been especially important because the condition disrupts cardiolipin and mitochondrial function. Long-term studies reported changes in muscle strength, exercise measurements, and heart function among some participants. In 2025, the FDA granted Forzinity accelerated approval based on improved knee-extensor muscle strength, which is considered reasonably likely to predict a meaningful benefit. A confirmatory study is required to determine whether this improvement translates into benefits such as standing more easily or walking farther.
Results in other conditions have been mixed. A large Phase 3 study involving primary mitochondrial myopathy found that elamipretide did not significantly improve walking distance or fatigue compared with a placebo after 24 weeks. Heart-failure studies have generally found acceptable tolerability but have not consistently demonstrated improvements in their primary measurements. Researchers have also explored SS-31 in age-related macular degeneration, kidney disease, aging, and neurological conditions, but these uses remain investigational.
WHAT IS SS-31 MOST COMMONLY RESEARCHED FOR?
SS-31 is most commonly researched for conditions involving damaged or poorly functioning mitochondria. These include Barth syndrome, primary mitochondrial myopathy, heart failure, kidney injury, retinal disease, neurological damage, muscle fatigue, and age-related declines in cellular energy. The peptide’s FDA-approved use is currently limited to improving muscle strength in certain patients with Barth syndrome, and research findings from that rare condition cannot automatically be applied to other health concerns.
HOW DOES SS-31 FIT INTO PEPTIDE RESEARCH?
SS-31 helps researchers explore whether a peptide can act directly within mitochondria rather than first attaching to a receptor on the outside of a cell. Its research connects membrane structure, energy production, oxidative stress, and tissue function. It also provides a way to investigate whether stabilizing one specialized part of the mitochondrial membrane can influence broader changes in muscles, the heart, the eyes, and other energy-demanding tissues.
WHAT MAKES SS-31 UNIQUE?
SS-31 stands out because it is an extremely small peptide that concentrates near the inner mitochondrial membrane without relying on the membrane’s electrical charge in the same way as many other mitochondria-targeting compounds. Its interaction with cardiolipin places it close to the machinery responsible for energy production. Rather than simply acting as a general antioxidant, SS-31 is studied for its ability to influence the membrane environment where excess reactive oxygen molecules may originate.
HOW IS SS-31 DIFFERENT FROM MOTS-C?
SS-31 and MOTS-C are both connected with mitochondrial research, but they are very different peptides. SS-31 is a synthetic four-amino-acid peptide designed to reach the inner mitochondrial membrane and interact with cardiolipin. MOTS-C is a naturally occurring, mitochondria-derived peptide that communicates with other parts of the cell and is studied for its possible influence on metabolism, glucose use, stress response, and gene activity.
WHAT HAVE RESEARCHERS LEARNED ABOUT SS-31 SO FAR?
Researchers have learned that SS-31 can bind to mitochondrial membranes and influence their structure, surface properties, and function in laboratory models. Animal studies have reported improvements across several forms of mitochondrial stress, but human results have been more variable. Research in Barth syndrome contributed to accelerated FDA approval, while larger studies involving primary mitochondrial myopathy and heart failure did not meet important primary goals. These differences show that mitochondrial dysfunction is complex and that benefits observed in one condition may not carry over to another.
IS RESEARCH ON SS-31 CONTINUING TODAY?
Yes. Research continues in Barth syndrome and other conditions involving mitochondrial dysfunction. The FDA requires a post-approval study to confirm the clinical benefit of Forzinity, while separate research is examining specific forms of mitochondrial myopathy and other possible applications. Scientists also continue investigating precisely how SS-31 interacts with cardiolipin, membrane proteins, calcium, and the cellular energy system.