SS-31 (Elamipretide): Structure, Research Overview and Specifications
SS-31, also known as elamipretide, is a small synthetic tetrapeptide that concentrates in the inner mitochondrial membrane, where it binds to the phospholipid cardiolipin. It is studied for its effects on mitochondrial energy production and oxidative stress. This page summarises its chemistry, the published research and the specifications of the material we supply.
For in vitro research use only. Not for human or animal use. Nothing on this page is medical advice.
What is SS-31?
SS-31 is a four-amino-acid peptide designed to cross cell membranes and accumulate in mitochondria, the structures that produce most of a cell’s energy. In the research literature it also appears as elamipretide, MTP-131 and Bendavia.
Unlike many mitochondria-targeted compounds, SS-31 does not rely on the mitochondrial membrane potential to get inside. Its alternating aromatic and positively charged residues let it pass through membranes and bind selectively to cardiolipin, a lipid found almost only in the inner mitochondrial membrane.
Chemical data
| Name | SS-31 (Elamipretide) |
|---|---|
| Other names | MTP-131, Bendavia |
| Sequence | D-Arg-Dmt-Lys-Phe-NH2 (Dmt = 2′,6′-dimethyltyrosine) |
| Length | 4 amino acids (C-terminal amide) |
| Molecular formula | C32H49N9O5 |
| Molecular weight | ≈ 639.8 g/mol (free base) |
| CAS number | 736992-21-5 |
| Form supplied | Lyophilised (freeze-dried) powder |
Origin: the Szeto-Schiller peptides
SS-31 is part of a series of small aromatic-cationic peptides developed by Hazel Szeto and Peter Schiller, which is where the “SS” name comes from. The series was originally explored for opioid receptor research, but some members, including SS-31, were found to concentrate in mitochondria and protect them from oxidative damage without opioid activity.
SS-31 was later developed under the name elamipretide and has since been studied in a wide range of laboratory and clinical research on mitochondrial function.
Proposed mechanisms studied
- Cardiolipin bindingSS-31 binds selectively to cardiolipin in the inner mitochondrial membrane, helping to preserve the membrane’s structure.
- Electron transport chainBy stabilising cardiolipin, SS-31 has been reported to support the function of the electron transport chain and ATP production.
- Oxidative stressStudies report reduced production of reactive oxygen species (ROS) from mitochondria and protection of cardiolipin from peroxidation.
- Cristae structureResearch links SS-31 to preserving the folded inner-membrane structure (cristae) where energy production takes place.
What the published research shows
Ischaemia and reperfusion models
Early laboratory studies examined SS-31 in models of ischaemia–reperfusion injury in the heart and kidney, reporting faster recovery of mitochondrial energy production after blood flow was restored.
Ageing and skeletal muscle
Studies in aged mice reported that SS-31 rapidly improved mitochondrial energetics in skeletal muscle and was associated with improved exercise tolerance in laboratory tests.
Clinical research in mitochondrial disease
Elamipretide has been studied in clinical trials in conditions involving mitochondrial dysfunction, including Barth syndrome, a rare genetic disorder of cardiolipin metabolism, and primary mitochondrial myopathy. Results have been mixed across studies and endpoints.
Other research areas
SS-31 is also used in laboratory research on heart failure, kidney injury, neurodegeneration and age-related eye disease models, where mitochondrial dysfunction is thought to play a role.
Limitations of the evidence
- Much of the mechanistic evidence comes from cell culture and animal models, which do not necessarily translate to humans.
- Clinical trial results have been mixed, with several studies not meeting their primary endpoints.
- Evidence from one disease model or tissue cannot be assumed to apply to others.
- Long-term effects remain under investigation.
Regulatory status
In September 2025, the US FDA granted accelerated approval to elamipretide (brand name Forzinity) as a treatment for Barth syndrome. It is not approved as a medicine in the UK. The SS-31 we supply is a research-grade compound, not a licensed medicinal product, and is sold strictly for in vitro laboratory research. It is not intended for human or animal use.
Storage and handling in the lab
- Store lyophilised powder at −20 °C, protected from light and moisture, for long-term stability.
- Allow the vial to reach room temperature before opening to reduce condensation.
- Once reconstituted for experiments, keep refrigerated (2–8 °C) and avoid repeated freeze–thaw cycles.
- SS-31 is water-soluble; prepare working solutions as needed for each experiment.
Quality
Every batch of SS-31 we supply is independently tested for purity by Janoshik using HPLC before it is released for sale. Read more on our Quality & Testing page.
Related research compounds
Frequently asked questions
Is SS-31 the same as elamipretide?
Yes. SS-31 is the original research name for the peptide later developed as elamipretide. It has also been referred to as MTP-131 and Bendavia.
What does SS-31 target?
SS-31 targets the inner mitochondrial membrane, where it binds to cardiolipin, a phospholipid that supports the electron transport chain and energy production.
What does “SS” stand for?
The name comes from Szeto and Schiller, the researchers who developed this family of small aromatic-cationic peptides.
Is SS-31 approved for human use in the UK?
No. Elamipretide received accelerated approval in the US in 2025 for Barth syndrome, but it is not approved in the UK. The research-grade SS-31 we supply is for laboratory research only and is not a licensed medicine.
How should SS-31 be stored?
Lyophilised SS-31 should be stored at −20 °C, protected from light and moisture. Reconstituted solutions should be kept refrigerated and not repeatedly frozen and thawed.
References
- Szeto HH, Schiller PW. Novel therapies targeting inner mitochondrial membrane: from discovery to clinical development. Pharmaceutical Research. 2011;28(11):2669–2679.
- Birk AV, et al. The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin. Journal of the American Society of Nephrology. 2013;24(8):1250–1261.
- Szeto HH. First-in-class cardiolipin-protective compound as a therapeutic agent to restore mitochondrial bioenergetics. British Journal of Pharmacology. 2014;171(8):2029–2050.
- Siegel MP, et al. Mitochondrial-targeted peptide rapidly improves mitochondrial energetics and skeletal muscle performance in aged mice. Aging Cell. 2013;12(5):763–771.
- Thompson WR, et al. A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome. Genetics in Medicine. 2021;23(3):471–478.
This page is for scientific information only. Sterling Research Group Ltd supplies SS-31 strictly for in vitro laboratory research. Not for human or animal use, and not for diagnostic or therapeutic purposes. Questions: [email protected]