SS-31 (also called elamipretide or MTP-131) is a mitochondria-targeting tetrapeptide that concentrates on the inner mitochondrial membrane and binds cardiolipin, the lipid that organizes the electron-transport chain. By stabilizing cristae and cutting reactive-oxygen-species production, it is studied for conditions of mitochondrial dysfunction — heart failure, ischemia-reperfusion injury, mitochondrial myopathy, and cellular aging. As elamipretide it has run human clinical trials (e.g. Barth syndrome) but is not FDA-approved; vendor-sold SS-31 is research-grade material.
Research notes
How does SS-31 work?
SS-31 is a small mitochondria-targeting tetrapeptide. Its alternating aromatic-cationic structure lets it cross cell membranes and concentrate on the inner mitochondrial membrane, where it binds cardiolipin — the signature phospholipid that scaffolds the electron-transport chain. By stabilizing cardiolipin and cristae architecture, it improves electron-transport efficiency and reduces the reactive-oxygen-species (ROS) leak that drives mitochondrial damage.
Unlike general antioxidants, the effect is structural: it protects the place where energy is actually made, which is why research interest centers on high-energy tissue (heart, skeletal muscle, kidney, retina) and on aging models where mitochondrial function declines.
What doses are used in research?
As elamipretide, human trials have used subcutaneous dosing broadly in the ~4–40 mg/day range depending on indication. Preclinical work spans a wide dose range by model. Research vials are commonly 10–50 mg.
What does this guide cover?
For SS-31, vendor scrutiny centers on COA-verified identity and purity. It is a non-standard sequence (D-amino acids, dimethyltyrosine), so synthesis quality varies and mass-spec identity confirmation matters more than usual. Cross-lab agreement on a published batch is the signal we weight most heavily.
Related reading
What it's researched for
- mitochondrial dysfunction
- cellular aging
- cardiac and skeletal-muscle bioenergetics
Where to source it
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Frequently asked about SS-31
What is SS-31?
SS-31 is a synthetic, cell-permeable tetrapeptide (D-Arg-dimethylTyr-Lys-Phe-NH2) that accumulates several-hundred-fold in the inner mitochondrial membrane and binds cardiolipin. It is studied as a mitochondrial-protective agent. The clinical-development name is elamipretide (also MTP-131, formerly Bendavia).
Is SS-31 the same as elamipretide?
Yes. SS-31, elamipretide, and MTP-131 are the same molecule. "SS-31" is the research designation; "elamipretide" is the clinical-development name used by Stealth BioTherapeutics. Bendavia was an earlier code name.
Is SS-31 FDA-approved?
No. As elamipretide it has been evaluated in human trials (including Barth syndrome and primary mitochondrial myopathy) but is not approved by the FDA for any indication as of 2026. Vendor-sold SS-31 is research-grade, not a medicine.
How is SS-31 purity verified?
The same way as any research peptide: a per-batch Certificate of Analysis with HPLC purity and mass-spec identity. Run a vendor COA through our /tools/coa-verifier. Vendors selling SS-31 with no published per-batch COA are unverified.