SS-31, also known as elamipretide, is a small synthetic peptide that concentrates in mitochondria and binds cardiolipin, a lipid found in the inner mitochondrial membrane. It has been studied extensively in preclinical models of mitochondrial dysfunction and investigated in clinical trials. This guide explains what SS-31 is, how it is thought to work, where it has been studied and how to handle it in the lab.
What is SS-31 (elamipretide)?
SS-31 belongs to the Szeto-Schiller (SS) peptides, a series of cell-permeable, mitochondria-targeted peptides named after the researchers who developed them. It has also appeared in the literature under the names MTP-131 and Bendavia, and elamipretide is its nonproprietary name.
SS-31 is a tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH2, where Dmt is 2',6'-dimethyltyrosine. Its design alternates aromatic and positively charged residues. That pattern lets it cross cell membranes and accumulate at the inner mitochondrial membrane without relying on the membrane potential that drives many other mitochondria-targeted molecules. The D-arginine at the start and the amidated C-terminus help protect it from enzymatic breakdown.
SS-31 supplied by PRIME is research material intended for laboratory use only.
How SS-31 works: mechanism studied in research
The inner mitochondrial membrane houses the electron transport chain, the set of protein complexes that generates most of a cell's ATP. Cardiolipin is a lipid almost unique to this membrane. It helps hold the respiratory complexes in place, shapes the folds (cristae) of the membrane and supports efficient electron transfer. When cardiolipin is oxidized or lost, as happens in many models of mitochondrial disease and aging, energy production falls and reactive oxygen species rise.
Research on SS-31 has focused on these points:
- Cardiolipin binding: SS-31 interacts selectively with cardiolipin, and this is thought to be its primary mode of action.
- Protection of membrane structure: in models, SS-31 has been associated with preserved cristae architecture and stabilized respiratory complexes.
- Electron transport efficiency: studies report improved coupling of electron transport and ATP production in stressed mitochondria.
- Reduced oxidative stress: SS-31 has been linked to lower mitochondrial reactive oxygen species and less cardiolipin peroxidation in cell and animal models.
- Cytochrome c interactions: research suggests SS-31 influences how cytochrome c interacts with cardiolipin, which is relevant to both electron transfer and cell death signaling.
A notable feature in many studies is that SS-31 appears to have little effect on healthy mitochondria and more effect on those under stress, which makes it a useful tool for separating mitochondrial injury from normal function.
How SS-31 differs from other mitochondrial compounds
Many compounds aimed at mitochondria are antioxidants that carry a positively charged group, such as a triphenylphosphonium tag, so that the membrane potential pulls them into the organelle. These approaches depend on mitochondria being healthy enough to hold a strong potential, which can limit uptake in exactly the damaged mitochondria researchers want to study. SS-31 takes a different route: its uptake is described as largely independent of membrane potential, and its main action is attributed to binding cardiolipin rather than scavenging radicals directly.
SS-31 also differs from compounds that work upstream of mitochondria, such as NAD+ precursors that support the supply of an essential coenzyme, or signaling peptides such as MOTS-c that act on metabolic pathways across the cell. For that reason, studies sometimes compare SS-31 with these compounds to separate structural protection of the inner membrane from broader metabolic effects.
Areas of research
SS-31 has been studied in cell culture, many animal models and clinical trials. Research areas include:
- Primary mitochondrial disease: clinical investigation in conditions such as primary mitochondrial myopathy and Barth syndrome, a disorder of cardiolipin metabolism
- Cardiac research: heart failure and ischemia-reperfusion injury models
- Kidney research: acute kidney injury and renal ischemia models
- Aging research: mitochondrial function in aged muscle, heart and other tissues in rodents
- Eye and neurological models: retinal and neurodegeneration models linked to mitochondrial dysfunction
SS-31 key facts table
| Property | Detail |
|---|---|
| Compound class | Synthetic mitochondria-targeted peptide (Szeto-Schiller series) |
| Other names | Elamipretide, MTP-131, Bendavia |
| Sequence | D-Arg-Dmt-Lys-Phe-NH2 (tetrapeptide) |
| Primary target | Cardiolipin in the inner mitochondrial membrane |
| Form supplied | Lyophilized powder in a sealed vial |
| Research status | Supplied by PRIME as research material for laboratory use only |
| Storage | Lyophilized: cold, dry, dark. Reconstituted: refrigerated |
Handling and storage in the lab
SS-31 is supplied as a lyophilized powder. General lab handling points:
- Equilibrate before opening: let the vial reach room temperature so moisture does not condense on the powder.
- Reconstitution: for lab use, reconstitute with bacteriostatic water or an assay-appropriate buffer. Add the diluent slowly and swirl gently; do not shake.
- Dry storage: keep sealed vials cold, dry and away from light, with a freezer preferred for long-term storage.
- Solution storage: refrigerate reconstituted material, protect it from light and aliquot to avoid repeated freeze-thaw cycles.
- Controls: in mitochondrial assays, include vehicle controls prepared with the same diluent, since buffer composition can affect respiration measurements.
Quality and lab results
Because SS-31 relies on specific non-natural residues such as D-arginine and dimethyltyrosine, identity testing matters: a peptide with the wrong stereochemistry or a missing modification would not behave the same way. Every PRIME batch is tested, and the certificate of analysis for each lot is published. Review current reports on the lab results page and match the lot number to your vial.
Research material is available as SS-31 (elamipretide).
Related research
- MOTS-c vs SS-31: a mitochondria-derived signaling peptide compared with a mitochondria-targeted one
- MOTS-c research guide: metabolic research on a peptide encoded in mitochondrial DNA
- NAD+ research guide: the coenzyme at the center of mitochondrial energy metabolism
SS-31 FAQ
What is SS-31?
SS-31 is a synthetic tetrapeptide, D-Arg-Dmt-Lys-Phe-NH2, that targets the inner mitochondrial membrane and binds cardiolipin. It is also known as elamipretide and is studied in research on mitochondrial dysfunction.
Are SS-31 and elamipretide the same compound?
Yes. SS-31 is the original research code from the Szeto-Schiller peptide series, and elamipretide is its nonproprietary name. It has also been called MTP-131 and Bendavia.
What does SS-31 do in mitochondria?
In research models, SS-31 binds cardiolipin and has been associated with preserved membrane structure, more efficient electron transport and lower oxidative stress in stressed mitochondria. It appears to have little effect on healthy mitochondria in many studies.
What is the difference between SS-31 and MOTS-c?
SS-31 is a synthetic peptide designed to act inside mitochondria on cardiolipin. MOTS-c is a naturally occurring peptide encoded in mitochondrial DNA that is studied mainly as a metabolic signaling molecule acting in the cell and body.
How should SS-31 be stored?
Store lyophilized vials cold, dry and protected from light. After reconstitution for lab use, refrigerate the solution, keep it out of light and avoid repeated freezing and thawing.
For laboratory research use only. Not for human consumption. Not a drug, food or cosmetic.