SS-31 (Elamipretide): Mitochondria-Targeted Peptide Research Guide (2026)
Last updated
Introduction (research-only scope)
SS-31 is a small aromatic-cationic tetrapeptide that concentrates in the inner mitochondrial membrane, where it binds the phospholipid cardiolipin. Under the generic name elamipretide it is the most clinically advanced compound in this catalog: in September 2025 it became the first mitochondria-targeted therapeutic to receive FDA approval. This guide explains the mechanism, the evidence and what that approval does and does not mean for research material.
Research use only. The material described here is a laboratory reagent for in-vitro research by qualified professionals. It is not a medicine, supplement, cosmetic ingredient or veterinary product, is not for human or animal use, and nothing on this page is medical advice or a claim of effect in any person.
What is SS-31?
SS-31 (molecular mass 640.77, CAS 736992-21-5) belongs to the Szeto-Schiller peptide series developed at Cornell. Its alternating aromatic and cationic residues drive accumulation in the inner mitochondrial membrane without a targeting sequence. Peptra Labs supplies it as a lyophilised research reagent, 10 mg per vial.
How the reported mechanism works
Cardiolipin binding
The reported mechanism is association with cardiolipin, the signature phospholipid of the inner mitochondrial membrane, which the literature links to cristae architecture and electron-transport-chain efficiency rather than to classical receptor signalling.
Structure-activity work
A 2022 eLife paper mapped structure-activity relationships across this tetrapeptide series, which is the reference for anyone designing comparisons between SS-31 and its analogues.
What the published evidence covers
The clinical record is real and, unusually here, positive in a narrow indication: elamipretide received FDA accelerated approval in September 2025 to improve muscle strength in Barth syndrome, based on a knee-extensor strength endpoint, with continued approval contingent on confirmatory trials. A 2024 post hoc analysis in Orphanet Journal of Rare Diseases examined genotype-specific effects in primary mitochondrial myopathy. Those results describe the pharmaceutical product in defined patient populations under medical supervision.
How to verify a SS-31 research peptide is real and pure
Two tests answer two different questions: mass spectrometry confirms identity (expected molecular mass 640.77), HPLC quantifies purity. Our specification is at least 98%. Check the batch number printed on your vial against the lab reports archive: where a batch has been tested, its report is published there and links to the testing laboratory’s own verification page. If your batch is not listed yet, ask us for its documentation before use; a “typical” certificate is not evidence for a specific vial. See how to read a certificate of analysis.
Storage and reconstitution
Store the lyophilised material sealed, dry and protected from light at 2 to 8 °C for routine laboratory use, colder for long-term archiving. After reconstitution with bacteriostatic water, keep refrigerated and use within the window your protocol defines; repeated freeze-thaw cycles degrade peptides. General handling for all our reagents is in the peptide storage protocol.
Regulatory status
Elamipretide holds FDA accelerated approval in the United States (September 2025) for a specific ultra-rare indication; that approval attaches to the pharmaceutical product and its manufacturer, not to research-grade material, and we make no statement about European marketing status, which can be checked in the EMA register. The reagent supplied here carries no marketing authorisation. SS-31 is not named individually on the WADA Prohibited List; because an approval now exists in one jurisdiction, athletes should check the live list rather than assume any category. Research-grade material supplied here is not a medicine and is for in-vitro laboratory use only. The wider framework, including anti-doping status, is described in the peptide risk profile.
Why labs choose our SS-31
Batch-numbered vials, published reports where a batch has been tested, shipping from an EU warehouse with tracking (no customs inside the EU) and prices shown with VAT included. Product page: SS-31 10 mg. Country-by-country sourcing questions are covered in the buyer guide Buy SS-31 in Europe.
References
- Structure-activity relationships of mitochondria-targeted tetrapeptide pharmacological compounds. eLife. 2022. PubMed 35913044
- Genotype-specific effects of elamipretide in patients with primary mitochondrial myopathy: a post hoc analysis. Orphanet J Rare Dis. 2024. PubMed 39574155