Buy SS-31 2026 — Mitochondria-targeted tetrapeptide for cardiolipin research (EU)

Peptide Research · 14 July 2026 · 10 min read · Research Use Only

SS-31 at a glance

What is SS-31?

SS-31 is a fully synthetic tetrapeptide that stems from the work of Hazel Szeto and Peter Schiller — the class of substances is named after them: Szeto-Schiller peptides. It also appears in databases and the literature as elamipretide and MTP-131.

Structurally, SS-31 consists of four amino acids in the sequence D-Arg-Dmt-Lys-Phe-NH₂. Two details make it chemically unusual: D-arginine is present in the D-configuration, the mirror image of the L-form usual in proteins, and at the second position is 2,6-dimethyltyrosine, a non-proteinogenic amino acid. The C-terminus is amidated. Both features are described in the peptide chemistry literature as common design elements of synthetic sequences. Also characteristic is the alternating pattern of aromatic (Dmt, Phe) and cationic (Arg, Lys) residues – described as the basis for this class passing through membranes without transporters in cell models.

Molecular profile & target structure

The molecular formula of the free base is C₃₂H₄₉N₉O₅ with a theoretical molar mass of approximately 639.8 g/mol; the CAS number 736992-21-5 is used for identification in databases. As a laboratory product, SS-31 is usually supplied as a salt – the salt form and peptide content can be found on the COA, not in the formula of the free base.

The specialist literature describes the target structure not as a classic receptor, but as a membrane lipid: cardiolipin, a phospholipid that occurs almost exclusively in the inner mitochondrial membrane, where it is associated with the organisation of the cristae and the respiratory chain.

What in-vitro and animal model studies document

The following summary reflects only what is described in the publicly accessible preclinical literature – it is not a statement about an effect or suitability in humans.

• Cardiolipin interaction: Published in vitro studies investigate SS-31 in relation to binding to cardiolipin in model membranes and isolated mitochondria.
• Cristae architecture: Several papers document electron microscopic observations of mitochondrial cristae structure in rodent models.
• Bioenergetics In-vitro studies describe measurements of oxygen consumption, membrane potential, and ATP content in isolated mitochondria and cell cultures.
• Redox-Marker: Animal model studies document observations on glutathione redox status in the skeletal muscle of aged mice.
• Ischaemia-Reperfusion Research:::: Published work examines SS-31 in animal models on cardiac and kidney tissue. These are study models, not applications.

These observations stem from in-vitro and animal models. They justify research interest in mitochondria-targeted peptides, but make no claims about safety or efficacy outside of laboratory research.

For context: Elamipretide is under investigation in clinical trials; the US Food and Drug Administration (FDA) granted accelerated approval in September 2025 for a prescription-only preparation for a rare indication. This concerns a finished medicinal product under medical supervision – from this it can be inferred no suitability or transferability to research material.

Purity, COA & Analytical Testing

In the case of a sequence containing non-proteinogenic building blocks, analytical testing is the key indicator of quality: deletion sequences, diastereomers or residual protecting groups are immediately apparent in the chromatogram. Every BlitzLab batch is analysed externally — RP-HPLC for purity (≥99%), LC-MS for molecular mass. Check the batch number, analysis date, peak purity and measured mass in the COA. How to read the document is explained Understanding and reading a Certificate of Analysis (COA); describes the methods Peptide Purity: HPLC and LC-MS Explained.

Storage & Handling

As a lyophilised powder in the unopened vial, SS-31 is stable under refrigeration and protected from light; for longer storage, freezing is usually chosen. Avoid temperature changes and moisture - vials should reach room temperature before opening. In dissolved state, stability is significantly reduced; aliquoting and avoidance of freeze-thaw cycles are standard. Details: Storing and Handling Research Peptides.

Buying SS-31 in the EU – what matters

The research peptide market is confusing, and particularly with demanding syntheses, batches vary considerably. Before ordering, you should clarify:

• Batch-related COA A sample certificate without batch reference is worthless – the batch number on the vial must match the document.
• Independent analysis: A third-party laboratory is more conclusive than a manufacturer's report, and only LC-MS proves identity, which a mere HPLC figure cannot show.
• Specification: Salt form, peptide content and filling quantity should be documented.
• Clear RUO Labelling A provider giving application or dosage instructions is exceeding the permissible scope – a warning sign, not a service.

What else to look out for when choosing a provider: 7-point checklist.

Frequently asked questions about buying SS-31

Note on Sources & RUO

The material information is based on public database entries (including PubChem) and on peer-reviewed publications searchable via PubMed concerning Szeto-Schiller peptides; the observations originate from in vitro systems and animal models. SS-31 is supplied exclusively as research material (Research Use Only): not for human or animal use, not as a food, dietary supplement, cosmetic, or medicinal product.