Introduction
SS-31 (also known as Elamipretide, MTP-131, or Bendavia) is a synthetic tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH₂, where Dmt is 2′,6′-dimethyltyrosine. It belongs to the Szeto-Schiller (SS) family of mitochondria-targeted peptides, developed by Hazel Szeto and Peter Schiller at Weill Cornell Medical College. SS-31 is one of the most extensively studied mitochondria-targeted research compounds, with a substantial body of preclinical data and a growing clinical research programme.
All SS-31 products supplied by Alpha Peptides are intended strictly for in vitro and laboratory research use only and are not approved for human or veterinary administration.
Structure & Background
SS-31 is a cell-permeable peptide that selectively concentrates in the inner mitochondrial membrane, achieving mitochondrial concentrations several hundred-fold higher than cytoplasmic concentrations. This selective mitochondrial targeting is driven by the alternating aromatic and cationic residues in its sequence, which interact with the negatively charged cardiolipin-rich inner mitochondrial membrane.
The inclusion of Dmt (dimethyltyrosine) rather than standard tyrosine confers enhanced antioxidant activity and resistance to enzymatic degradation, making SS-31 a more stable and potent research tool than earlier SS-peptide analogues.
Proposed Mechanisms of Action
- Cardiolipin binding and stabilisation: SS-31’s primary mechanism is its high-affinity binding to cardiolipin, a phospholipid found almost exclusively in the inner mitochondrial membrane. Cardiolipin plays a critical structural role in organising the electron transport chain (ETC) complexes into supercomplexes, and its peroxidation during oxidative stress disrupts ETC function and triggers apoptosis. SS-31 binding protects cardiolipin from peroxidation, preserving ETC supercomplex organisation and mitochondrial membrane integrity.
- Reactive oxygen species (ROS) scavenging: The Dmt residue confers direct antioxidant activity, enabling SS-31 to scavenge reactive oxygen species generated at the inner mitochondrial membrane. This reduces oxidative damage to mitochondrial proteins, lipids, and DNA.
- ATP synthesis preservation: By maintaining ETC supercomplex organisation and reducing oxidative damage to ETC components, SS-31 preserves mitochondrial ATP synthesis capacity under conditions of stress. Studies have reported improved ATP production in SS-31-treated cells and tissues subjected to ischaemia, hypoxia, or other mitochondrial stressors.
- Cytochrome c retention: SS-31 has been shown to reduce the release of cytochrome c from mitochondria — a key step in the intrinsic apoptosis pathway — by stabilising cardiolipin and maintaining inner membrane integrity.
- Mitochondrial morphology preservation: Research has reported that SS-31 helps maintain normal mitochondrial morphology (preventing excessive fragmentation) under stress conditions, which is associated with preserved mitochondrial function.
Key Research Findings
Ischaemia-Reperfusion Injury
The most extensively studied application of SS-31 is protection against ischaemia-reperfusion (I/R) injury, where the restoration of blood flow to ischaemic tissue paradoxically causes a burst of ROS production that damages mitochondria and triggers cell death. Animal studies across cardiac, renal, hepatic, and cerebral I/R models have consistently demonstrated significant protection with SS-31 pre- or post-treatment, including reduced infarct size, preserved organ function, and improved survival outcomes.
Cardiac Research
SS-31 has been extensively studied in cardiac models. Beyond I/R injury, research has investigated its effects in heart failure models, reporting improved cardiac function, reduced fibrosis, and preserved mitochondrial ultrastructure in treated animals. A clinical programme (Stealth BioTherapeutics) investigated Elamipretide in human heart failure, with Phase II data reporting improvements in exercise capacity and cardiac function in some patient subgroups.
Renal Research
Renal ischaemia-reperfusion injury and chronic kidney disease models have shown significant protection with SS-31, including preserved glomerular filtration rate, reduced tubular injury markers, and improved mitochondrial function in renal tubular cells. This has made SS-31 a widely used research tool in nephrology research.
Ageing & Mitochondrial Dysfunction Research
Research has investigated SS-31 in the context of age-related mitochondrial decline, reporting improvements in mitochondrial function, reduced oxidative stress markers, and improved physical performance in aged animal models. This has generated interest in mitochondria-targeted peptides as research tools for studying the role of mitochondrial dysfunction in biological ageing.
Skeletal Muscle Research
Studies have explored SS-31 in models of skeletal muscle atrophy and dysfunction, reporting preserved muscle mass, improved mitochondrial function, and enhanced exercise capacity in treated animals. This research intersects with both ageing biology and metabolic disease research.
Research Considerations
- SS-31 is one of the few mitochondria-targeted research peptides with both substantial preclinical data and human clinical trial experience, making it a particularly well-characterised research tool.
- Its selective mitochondrial accumulation means that relatively low concentrations can achieve high local concentrations at the target site — an important consideration for experimental protocol design.
- SS-31 contains non-standard amino acids (Dmt, D-Arg) which contribute to its stability and activity but should be noted when interpreting structure-activity relationship data.
- Refer to the Certificate of Analysis (COA) supplied with each batch for purity and sequence confirmation data.
Reconstitution & Storage
SS-31 should be reconstituted with bacteriostatic water or sterile water to the required concentration. Store the reconstituted solution at 2–8°C and use within 28–30 days (bacteriostatic water) or 24 hours (sterile water). For full guidance, refer to our Peptide Reconstitution Guide and Storage & Handling Guide.
Research Resources
Researchers can source SS-31 10mg from Alpha Peptides, supplied with a full batch-specific COA. For related compounds studied in mitochondrial biology and longevity research, explore our Mitochondrial Research and Longevity Research collections.
Disclaimer: All products sold by Alpha Peptides are intended strictly for in vitro research and laboratory use only. They are not approved for human or veterinary use, and this article does not constitute medical advice.
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