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    Research Use Only (RUO). For laboratory research only. Not for human or veterinary use.

    Avenor Peptides
    Research Use Only (RUO):Research classification with product and batch documentation where available.
    SS-31 10 mg - Avenor Peptides

    Body composition

    SS-31

    Strength: 10 mg

    SS-31 is a research-use catalogue item organized around product identity, SKU traceability and available documentation.

    €69,00
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    Batch documentationShips from Greece

    Free shipping: Greece from €50, Cyprus and Bulgaria from €100, France, Germany, Italy, Belgium, Netherlands and Spain from €200. Details

    This product is intended exclusively for laboratory research use. It is not intended for human consumption, diagnosis, treatment, or prevention of disease.

    Product information

    FormResearch product
    Strength10 mg
    SKUAV-SS31-10MG
    Stock statusIn stock
    COA / BatchSee the documentation state below
    StorageIn powder form: freezer (−20°C).
    Packaging / shippingProtective professional shipping packaging with clear labelling.

    Documentation on request

    There is no published document for this specific SKU variant at the moment.

    Contact us about documentation

    Research overview

    Documentation & COA

    Batch documentation and COA, where available, are linked to the specific product batch and SKU.

    This product is intended exclusively for laboratory research use. It is not intended for human consumption, diagnosis, treatment, or prevention of disease.

    Product profile

    4

    amino acids — one of the smallest research peptides

    ~1000x

    concentration in the inner mitochondrial membrane (Zhao et al., 2004)

    218

    participants in the Phase III MMPOWER-3 trial

    ≥98%

    purity by HPLC

    Research context

    What it is

    SS-31 is a small synthetic peptide, just four amino acids. It targets one place only: the inside of the mitochondria.

    Mitochondria are the cell's power plants. When they wear down, the cell is left without fuel.

    The technical detail

    Also known as elamipretide, MTP-131 or Bendavia. It binds cardiolipin on the inner mitochondrial membrane.

    How it works

    Inside the mitochondria there is a lipid that keeps the energy 'production line' stable.

    SS-31 attaches to that lipid and steadies it. Energy production becomes more efficient, and fewer harmful free radicals are made.

    The technical detail

    Binding to cardiolipin stabilises the respiratory-chain supercomplexes and lowers reactive oxygen species production (Zhao et al., 2025).

    What the research shows today

    In September 2025 the molecule received its first approval: FDA accelerated approval for Barth syndrome, an ultra-rare mitochondrial disorder.

    It is the first targeted therapy approved for that disorder. Meanwhile, 2026 preclinical work is extending into the heart, spinal cord and lung.

    2025

    first FDA approval (Barth)

    168

    weeks, open-label extension

    67→38%

    cell senescence, radiation

    In the pivotal study the core crossover phase showed no statistically significant improvement; the benefit appeared in the long 168-week extension.

    Where it stands

    Beyond Barth, SS-31 is in advanced-stage testing for mitochondrial myopathies and for dry age-related macular degeneration.

    In the lab, in 2026, it was also studied in models of heart, spinal-cord and lung injury — always converging on the same point: protecting the mitochondria.

    The technical detail

    Developed by Stealth BioTherapeutics; phase III for dry AMD and mitochondrial myopathies (Shirley, Drugs, 2025).

    Laboratory use

    Used in a controlled laboratory setting for in vitro cardiolipin binding studies with liposomes and bicelles, for oxygen consumption and respiratory capacity measurements in isolated mitochondria and mitoplasts, for analysis of cytochrome c / cardiolipin complex peroxidase activity, for respiratory supercomplex organization studies by blue native electrophoresis, for mitophagy and mitochondrial morphology work in cell lines, and for identity and purity confirmation by HPLC and mass spectrometry.

    Research Use Only. For laboratory research exclusively. Not intended for human or veterinary use, diagnosis, treatment, or disease prevention. The clinical trials and regulatory events referenced concern a pharmaceutical product under development, manufactured and controlled to pharmaceutical specifications, and in no way constitute an indication or recommendation for use of this research material. The data are presented solely as scientific background.

    Structural data

    Class
    Aromatic-cationic mitochondria-targeting tetrapeptide (Szeto-Schiller peptide)
    Chain length
    4 amino acids, synthetic peptide
    Sequence
    D-Arg-Dmt-Lys-Phe-NH2 (Dmt = 2',6'-dimethyltyrosine)
    Molecular formula
    C32H49N9O5
    Molecular weight
    ≈639.8 g/mol (free base)
    Development codes
    SS-31, MTP-131, RX-31 — trade names Bendavia, Ocuvia
    ChEMBL identifier
    CHEMBL3833370
    Structural motif
    Alternating aromatic and basic residues; the dimethyltyrosine is the free-radical-scavenging element
    Molecular target
    Cardiolipin — an anionic phospholipid of the inner mitochondrial membrane. No receptor is involved
    Stereochemistry
    Carries a D-arginine at the N-terminus, conferring resistance to enzymatic degradation
    Product form
    Lyophilized powder in a sealed vial, 10 mg
    Purity
    ≥98% (HPLC) — supplied with CoA

    Comparison

    Feature comparison

    FeatureSS-31 / Elamipretide (this product)MOTS-cSLU-PP-332
    Molecule typeSynthetic tetrapeptide (4 amino acids)16-amino-acid peptide encoded in mitochondrial DNASmall synthetic molecule — not a peptide
    Where it actsDirectly at the inner mitochondrial membrane — binds cardiolipinCytoplasmic and nuclear signalling pathwaysNuclear ERR (estrogen-related receptor) proteins
    Receptor required?NO — it targets a lipid, not a protein receptorActs through signalling cascades (AMPK)YES — nuclear receptor agonist
    OriginDesigned by Szeto and Schiller (Weill Cornell)Endogenous peptide — derived from the 12S rRNA of mtDNADesigned in a medicinal chemistry programme
    Maturity of the evidenceCompleted Phase III trials; accelerated regulatory approval for Barth syndrome (Sept 2025)Preclinical data and early-stage studiesPreclinical data only
    Product formLyophilized powder (injectable vial)Lyophilized powder (injectable vial)Not supplied as a peptide

    Storage & handling

    • The sealed vial of lyophilized powder is stored frozen, protected from light and moisture.
    • Lyophilized material is hygroscopic — allow the vial to equilibrate to room temperature before opening to avoid moisture condensation.
    • After reconstitution the solution is stored refrigerated and handled as material of limited stability.
    • Avoid repeated freeze–thaw cycles, which degrade peptide integrity.
    • Avoid prolonged exposure to room temperature and to direct sunlight.
    • Handle using aseptic technique, standard laboratory practice and appropriate personal protective equipment.
    • Keep away from children and out of food preparation areas.

    Documentation

    • Certificate of Analysis (CoA) per batch, with date and lot number.
    • Purity analysis by HPLC — specification ≥98%.
    • Identity and molecular weight confirmation by mass spectrometry.
    • Research Use Only (RUO) declaration on the packaging.
    • Documents available on request for the specific batch you received.

    References

    References & documentation

    1. 1.Zhao K., Schiller P.W., Szeto H.H. et al. (2004). Cell-permeable peptide antioxidants targeted to inner mitochondrial membrane inhibit mitochondrial swelling, oxidative cell death, and reperfusion injury. J Biol Chem, 279(33), 34682-34690.
    2. 2.Birk A.V. et al. (2013). The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin. J Am Soc Nephrol, 24(8), 1250-1261.
    3. 3.Birk A.V. et al. (2014). Targeting mitochondrial cardiolipin and the cytochrome c/cardiolipin complex to promote electron transport and optimize mitochondrial ATP synthesis. Br J Pharmacol, 171(8), 2017-2028.
    4. 4.Liu S. et al. (2014). Novel cardiolipin therapeutic protects endothelial mitochondria during renal ischemia and mitigates microvascular rarefaction, inflammation, and fibrosis. Am J Physiol Renal Physiol, 306(9), F970-F980.
    5. 5.Karaa A. et al. (2018). Randomized dose-escalation trial of elamipretide in adults with primary mitochondrial myopathy (MMPOWER). Neurology, 90(14), e1212-e1221.
    6. 6.Petcherski A. et al. (2018). Elamipretide Promotes Mitophagosome Formation and Prevents Its Reduction Induced by Nutrient Excess in INS1 β-cells. J Mol Biol, 430(24), 4823-4833.
    7. 7.Chavez J.D. et al. (2020). Mitochondrial protein interaction landscape of SS-31. Proc Natl Acad Sci USA, 117(26), 15363-15373.
    8. 8.Karaa A. et al. (2020). A randomized crossover trial of elamipretide in adults with primary mitochondrial myopathy (MMPOWER-2). J Cachexia Sarcopenia Muscle, 11(4), 909-918.
    9. 9.Russo S. et al. (2022). Beneficial effects of SS-31 peptide on cardiac mitochondrial dysfunction in tafazzin knockdown mice. Sci Rep, 12(1), 19847.
    10. 10.Karaa A. et al. (2023). Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial. Neurology, 101(3), e238-e252.
    11. 11.Karaa A. et al. (2024). Genotype-specific effects of elamipretide in patients with primary mitochondrial myopathy: a post hoc analysis of the MMPOWER-3 trial. Orphanet J Rare Dis, 19(1), 431.
    12. 12.Zhao C. & Zhuang X. (2025). Elamipretide: The first cardiolipin-directed mitochondrial therapeutic for Barth syndrome approved under accelerated approval. Drug Discov Ther, 19(6), 435-436.

    Product information

    Frequently asked questions

    What is cardiolipin and why does it matter?
    Cardiolipin is a negatively charged phospholipid found almost exclusively in the inner mitochondrial membrane — it does not exist in meaningful quantity anywhere else in the cell. It is required for the formation of cristae, the folds where ATP is produced, and it holds cytochrome c of the respiratory chain in place. Because it is so localized, a molecule that binds it necessarily ends up inside mitochondria.
    Why is it called SS-31?
    The initials come from Hazel Szeto and Peter Schiller, who designed this peptide family at Weill Cornell Medical College. The literature refers to the class as Szeto-Schiller peptides. The 31 is the sequential number of this particular analogue within the screened series.
    Why does it need no receptor?
    Because its target is a lipid, not a protein. Nearly every peptide acts by docking onto a protein receptor; SS-31 binds cardiolipin directly through electrostatic and hydrophobic interactions. Zhao and colleagues (2004) measured roughly a thousand-fold concentration in the inner mitochondrial membrane relative to the rest of the cell.
    What did the clinical trials show — and what did they not?
    MMPOWER (Karaa et al., 2018) in 36 participants recorded a 64.5-metre increase on the six-minute walk test versus 20.4 metres on placebo, narrowly short of significance (p = 0.053). MMPOWER-3 (Karaa et al., 2023), Phase III with 218 participants, met none of its primary endpoints. That is a negative result and it is stated plainly here.
    If the Phase III trial failed, why is there an approval?
    It is a different indication. The MMPOWER trials concerned primary mitochondrial myopathy. As Zhao and colleagues record (2025), on 19 September 2025 the FDA granted accelerated approval for Barth syndrome, a rare disorder of cardiolipin remodeling, with a confirmatory trial required as an explicit condition.
    What did the MMPOWER-3 subgroup analysis show?
    The later analysis (Karaa et al., 2024) split participants by genotype. 74% carried mitochondrial DNA variants and did not differ from placebo. The subgroup with mtDNA replisome variants showed an improvement of 25.2 metres versus 2.0 (p = 0.06) — a trend, not a statistically significant finding, and drawn from an analysis that generates hypotheses.
    How does it compare with MOTS-c?
    Both relate to mitochondria but in entirely different ways. MOTS-c is an endogenous 16-amino-acid peptide encoded within mitochondrial DNA itself and acts through signalling pathways. SS-31 is a synthetic tetrapeptide that acts physically inside the membrane by binding a lipid. See the comparison table above.
    What are the open questions in the literature?
    It is unresolved whether the principal action is membrane stabilization, inhibition of cytochrome c peroxidase activity, or organization of respiratory supercomplexes. Russo and colleagues (2022) observed improved respiration without any change in the MLCL/CL ratio, supporting the third scenario. Which genotypes respond also remains open.
    Can it be used by humans or animals?
    No. The product is supplied exclusively for laboratory research. It is not intended for human or veterinary use, nor for in vivo application outside a controlled laboratory setting. No administration or dosing guidance is provided.
    Do I receive a certificate of analysis?
    Yes. Every batch is accompanied by a CoA with HPLC analysis and mass spectrometry identity confirmation. It is available on request for the specific batch you received.