SS31 10mg Research Peptide for Laboratory Use

Product Details and Specifications for This Research Peptide

Each vial contains only the peptide SS31 as a dry powder, with no water, solvent, filler or other active ingredient. It is a single compound, not a blend, so any result in your experiment can be attributed to SS-31 alone. Our SS-31 10mg vial suits labs that run several assays from one batch; SS31 10mg is also the most searched size, so make sure any SS31 peptide 10mg listing you compare against states the batch purity too.

It is not an SS 31 peptide supplement, and no form of SS-31 supplement, SS 31 peptide capsules, SS 31 peptide oral product or SS 31 nasal spray is a legal food supplement in the UK. This vial is a laboratory reagent only.

What Is SS 31 and Why Is It Also Called Elamipretide?

What is SS-31? It is one of the Szeto-Schiller (SS) peptides, a family of small synthetic peptides designed by Hazel Szeto at Weill Cornell Medicine in New York and Peter Schiller at the Clinical Research Institute of Montreal. The “SS” stands for their surnames and “31” is the compound’s number in the series. The early SS peptides came out of opioid-peptide chemistry; SS-31 was the one found to collect in mitochondria without acting on opioid receptors [VERIFY opioid-receptor wording].

Elamipretide is its official non-proprietary drug name, given when Stealth BioTherapeutics took it into clinical trials; it was earlier coded MTP-131 and called Bendavia. So SS31 elamipretide, SS-31 elamipretide and elamipretide SS 31 all mean the same molecule. In September 2025 the US Food and Drug Administration approved an elamipretide injection, Forzinity, for a rare disease (see the human studies section below). The peptide SS 31 sold for research has the same sequence, but it is a laboratory chemical, not that medicine.

Amino Acid Sequence, Molecular Weight and Chemical Structure

• Sequence: H-D-Arg-Dmt-Lys-Phe-NH2. Position 1 is D-arginine, the mirror-image form of the natural amino acid. Position 2 is Dmt (2′,6′-dimethyl-L-tyrosine), a tyrosine with two extra methyl groups on its ring. Positions 3 and 4 are L-lysine and L-phenylalanine, and the chain ends in an amide (–NH2) instead of an acid.
• Formula and weight: C32H49N9O5, average molecular weight about 639.8 g/mol, monoisotopic mass about 639.39.
• CAS number: 736992-21-5 (free base).
• Structure: the sequence alternates aromatic rings (Dmt, Phe) with positively charged groups (Arg, Lys). With the free N-terminal amine and the uncharged C-terminal amide, SS-31 carries a net charge of about +3 at neutral pH. This aromatic-cationic pattern is what lets it pass into cells and sit at the negatively charged inner mitochondrial membrane.
• Stability: the D-amino acid at position 1 and the C-terminal amide both make the chain harder for common enzymes to cut. The SS 31 peptide half life in blood is still short; published values differ with species and route [VERIFY: add a primary pharmacokinetic source if you quote a figure], so check the literature for your model before relying on an SS31 half life value.

How Is It Studied in Laboratory Research?

What is SS 31 peptide used for in the lab? It is used as a tool to study mitochondria under stress: how their inner membrane is organised, how they make energy, and what happens when they are damaged. Research on SS31 peptides falls into three main areas, below. Much of the early work came from Hazel Szeto’s group and from Stealth BioTherapeutics. The findings are from cells, isolated mitochondria and animal models. What is SS31 peptide used for outside the lab? Only one use is approved anywhere: the US medicine described in the human studies section.

Mitochondria and Cell Energy Research

Mitochondria make ATP, the molecule cells use for energy, on folds of their inner membrane called cristae. Because SS-31 concentrates at that membrane, it is often described as a mitochondrial peptide SS 31, although it is synthetic and is not made by mitochondria:

• Kidney ischaemia in rats: Birk et al. (2013) treated rats with SS-31 before cutting off blood supply to the kidney. In treated animals the cristae stayed intact, mitochondria did not swell, and ATP recovered faster once blood flow returned. Cell structure was repaired faster, fewer cells died, and kidney function was better preserved. This is the main SS 31 peptide kidney study.
• Uptake: the original 2004 study reported that SS-31 enters cells and concentrates in the inner mitochondrial membrane, about 1,000-fold over the surrounding fluid [VERIFY: Zhao et al. 2004].

These results describe what happens in specific models. They do not show any effect on energy, fitness or ageing in people.

Oxidative Stress Research in Cell Models

Oxidative stress is damage from reactive oxygen species (ROS), unstable molecules made in part by mitochondria. The 2004 paper that introduced SS-31 (Zhao et al.) tested it in cell models of this damage:

• Neuronal cell line: in N2A mouse neuroblastoma cells exposed to tert-butyl hydroperoxide (tBHP), a chemical that triggers oxidative damage, SS-31 reduced ROS and cell death [VERIFY: Zhao et al. 2004 abstract].
• Isolated mitochondria: the same paper reported that SS-31 inhibited mitochondrial swelling, a sign of damage, in isolated mitochondria.
• Antioxidant or not? SS-31 was first described as an antioxidant, but later work places more weight on its membrane effects (next section). Many researchers now describe it as protecting the membrane and its proteins, which reduces ROS production, rather than mainly mopping up ROS.

Cell survival in a dish is an early-stage finding. It does not show a treatment effect.

Cardiolipin Binding Research

Cardiolipin is a fat (phospholipid) found almost only in the inner mitochondrial membrane. It helps hold the cristae folds in shape and anchors the protein complexes that make ATP. Its negative charge is where the positively charged SS-31 binds, and this is the core of the SS-31 elamipretide mechanism of action:

• Binding: using a fluorescent version of the peptide, Birk et al. (2013) showed that SS-31 binds cardiolipin with high affinity.
• Cytochrome c: under stress, the protein cytochrome c can act as a peroxidase that damages cardiolipin. In the same study, the SS-31–cardiolipin complex blocked this activity by protecting cytochrome c’s haem iron.
• Membrane surface charge: Mitchell et al. (2020) found that SS-31 sits in the surface layer of membranes, with binding linked to surface charge. It did not disrupt the membranes even at high binding, but it changed how the lipids packed and the electrical charge at the surface, and it altered how calcium spread across the surface in mitochondria.

Together these studies explain the SS-31 elamipretide mechanism of action, mitochondria, cardiolipin link that most reviews describe. Barth syndrome, the one approved use, is itself a disease of faulty cardiolipin, which is why it was chosen for clinical trials.

What Does Current Evidence Say About Human Studies?

Elamipretide has been through several clinical trials, with mixed results:

• Heart attack (EMBRACE STEMI, Phase 2a): given through a drip during treatment for a heart attack, elamipretide did not reduce heart muscle damage or improve any secondary outcome (Gibson et al. 2016). It was well tolerated.
• Primary mitochondrial myopathy (MMPOWER-3, Phase 3): 218 adults received daily elamipretide injections or placebo for 24 weeks. The trial did not meet either primary endpoint, a 6-minute walk test and a fatigue score (Neurology, 2023).
• Barth syndrome (TAZPOWER): Barth syndrome is a rare inherited disease, mainly in boys and men, caused by a fault in cardiolipin. In the 12-week randomised, placebo-controlled part of TAZPOWER, elamipretide had no significant effect on the primary walking-test endpoint. Patients improved over a longer open-label extension of up to 168 weeks, and did better than untreated patients in a natural-history comparison (Hornby et al. 2022). Open-label and comparison data are weaker evidence than a randomised trial.
• FDA accelerated approval: is SS-31 FDA approved? Yes, as one medicine. On 19 September 2025 the FDA gave accelerated approval to Forzinity (elamipretide) injection for Barth syndrome in patients weighing at least 30 kg. Accelerated approval means it was based on a surrogate endpoint, here knee muscle strength, that the FDA considers reasonably likely to predict real benefit. The manufacturer must confirm the benefit in a randomised, placebo-controlled trial, and the Phase 4 4TAZPower study dosed its first patient in July 2026. So SS 31 FDA approved is true for that product only, and the SS31 FDA approval could still be withdrawn if the confirmatory trial fails.
• Other studies: a Phase 3 trial in dry age-related macular degeneration (ReNEW) is fully enrolled, with results expected in late 2027.

Elamipretide is not approved by the MHRA in the UK or the EMA in the EU [VERIFY before publishing]. The US approval covers Forzinity, a medicine made to pharmaceutical (GMP) standards and prescribed for one rare disease. It does not apply to research-grade SS-31, which is not made or tested to medicine standards. Genesis Peptides makes no health claims for this product.

SS 31 vs MOTS c: What Is the Difference in Research?

SS 31 peptide vs MOTS c is a common comparison, because both are linked to mitochondria. They are very different molecules: one is a synthetic drug-design compound that targets the mitochondrial membrane, the other is a natural peptide that mitochondria make themselves.

The main difference is the question each one answers. SS-31 is used to study what happens when the inner membrane and cardiolipin are protected. MOTS-c is used to study how mitochondria send signals to the rest of the cell. Searches for MOTS-c SS-31 or MOTS c SS31 often come from people looking to combine them, but in a study design, testing each one alone is the only way to know which caused a result. On a COA, the two are easy to tell apart: about 639.8 for SS-31 and about 2174.6 for MOTS-c. Anyone comparing SS31 peptide vs MOTS c should check both certificates. [LINK: MOTS-c vial, if stocked; otherwise delete]

Certificate of Analysis and Purity Testing for Each Batch

Every batch of our SS31 comes with a certificate of analysis (COA) from [CONFIRM: lab name] [independent third-party lab: CONFIRM]. The COA shows two separate tests: HPLC, which measures purity, and mass spectrometry, which confirms the molecule. Both are needed. A high purity figure alone does not prove the main peak is the SS-31 peptide, and a correct mass alone does not show how much of the sample is impurity.

How to Find and Download the Certificate for Your Batch

1. Find the batch number on your vial label [and on the packing slip: CONFIRM].
2. Go to [LINK: COA library page], or use the COA link in the product images on this page.
3. Choose the certificate whose batch number matches your vial and download the PDF.
4. If you cannot find your batch, contact us at [CONFIRM: email] and we will send it.

How to Read HPLC Purity and Mass Spectrometry Results

• HPLC purity: the trace shows one main peak for SS-31 and smaller peaks for impurities, such as shorter “deletion” sequences missing one amino acid, or a version where an amino acid has flipped to its mirror-image form. Purity is the main peak’s area as a percentage of all peaks. This batch: [CONFIRM: __%].
• Mass spectrometry: the measured monoisotopic mass should be about 639.39. Because SS-31 carries several positive charges, it often shows as [M+H]+ at about 640.4, [M+2H]2+ at about 320.7 or [M+3H]3+ at about 214.1. A neutral mass about 1 unit heavier (about 640.37, so [M+H]+ about 641.4) can mean the C-terminal amide has become an acid, a common synthesis impurity.
• Net peptide content (if shown): the share of the powder that is peptide, as opposed to counter-ions (acetate or chloride) and residual water. With three positive charges per molecule, the counter-ions can be a large share of the weight, so net content is often well below 100% even when purity is high.
• Check the details: the product name, batch number, test date and lab name should all be on the certificate.

How to Store and Handle a Lyophilised Peptide Vial

As a dry, lyophilised powder, SS-31 is much more stable than in solution. For long-term storage, keep the sealed vial at −20 °C, away from light and moisture. For short periods, 2–8 °C in a fridge is generally suitable for lyophilised peptides [CONFIRM in-house guidance], and short periods at room temperature during delivery are normal. Peptide salts attract water from the air, so before opening a cold vial, let it reach room temperature so moisture does not condense on the powder. Handle with gloves, using sterile technique, in a lab setting.

Storage Before and After Reconstitution

• Before reconstitution: sealed vial at −20 °C long term, or 2–8 °C short term. Shelf life unopened: [__ months: CONFIRM], and never past the expiry date on the label.
• SS-31 reconstitution: SS-31 is highly water-soluble because of its positive charges. In research protocols, the powder is usually dissolved in sterile water or bacteriostatic water [LINK: bac water], added slowly down the side of the vial and swirled gently rather than shaken. The volume depends on the concentration your assay needs; we do not give dosing or reconstitution charts. Notes on SS 31 reconstitution in published papers will name the solvent used, which is worth matching if you are repeating a study.
• After SS31 reconstitution: store the solution at 2–8 °C, protected from light, and use within [__ days/weeks: CONFIRM from your stability data]. Avoid repeated freezing and thawing; if longer storage is needed, split the solution into single-use aliquots and freeze them.
• Discard any solution that turns cloudy, changes colour or contains particles.

Is Research Use of This Peptide Legal in the UK, and Is It Banned in Sport?

[LEGAL REVIEW: this section]

These are the facts we can state; they are not legal advice.

• Not a controlled drug. SS-31 is not listed under the Misuse of Drugs Act 1971 [VERIFY].
• Not a licensed medicine in the UK. Elamipretide is approved as a prescription medicine in the US only. It has no marketing authorisation from the MHRA [VERIFY], so it cannot legally be sold or supplied in the UK as a medicine for human use, or as a food supplement.
• The US approval does not cover research vials. Searches for SS 31 peptide FDA approved or SS31 peptide FDA approved refer to Forzinity, a specific GMP-made injection from Stealth BioTherapeutics. That approval does not make research-chemical SS-31 a medicine, in the US or the UK.
• How we sell it. We supply the SS-31 peptide as a research chemical, labelled and sold for laboratory use and not for consumption [LEGAL REVIEW]. We will not sell to anyone who says they intend to use it on a person or an animal.

Is it banned in sport? SS-31 and elamipretide are not named on the World Anti-Doping Agency (WADA) 2026 Prohibited List. Section S0 bans pharmacological substances not covered by another section that have no current approval for human therapeutic use by any government health authority. Because elamipretide now has US approval, whether S0 applies is not clear-cut, and other sections could be relevant to a substance that acts on metabolism. Athletes covered by UK Anti-Doping (UKAD) rules should check with UKAD before any contact with it [VERIFY with UKAD]. MOTS-c, often mentioned alongside SS-31, is named on the list.

What to Check Before Buying Research Peptides in the UK

Before you buy SS-31 or any other research peptide, check:

• A batch-matched COA with both HPLC purity and mass spectrometry identity, from a named lab. For SS-31, the mass should be about 639.8.
• The exact compound. The listing should say SS-31 (D-Arg-Dmt-Lys-Phe-NH2), the amount per vial, and whether it is a single peptide or a blend. The Dmt residue is harder to make than a normal amino acid, so a correct mass matters.
• Net peptide content and salt form, so you know how much actual peptide is in the vial. The SS 31 peptide price per vial means little without this.
• Clear research-use labelling and no dosing, energy, anti-ageing or weight-loss claims. A supplier that makes them, or that suggests its vial is the FDA-approved medicine, is selling outside the rules.
• A UK address and contact details, and dispatch from the UK. If you buy SS31 peptide stock from overseas, it may be held at customs.

The lowest price is rarely the best value if there is no batch certificate behind it. Whether you buy SS-31 peptide online from us or anyone else, check the COA before you open the vial. To place an SS31 peptide buy order, add this vial to your basket at the top of this page.

UK Delivery, Dispatch and Packaging

• Dispatch: orders placed before [CONFIRM: time] on a working day are dispatched the same day from [CONFIRM: town/county].
• Delivery: [CONFIRM: carrier and service, e.g. Royal Mail Tracked 24], [CONFIRM: price / free over £__].
• Packaging: vials are sealed and packed in [CONFIRM: protective packaging details], in plain outer packaging. Lyophilised peptides are stable at room temperature for the length of normal UK transit; store them as described above on arrival [CONFIRM].
• Payment: [CONFIRM: payment methods].

Our SS 31 peptide UK stock is held and shipped within the UK, so there are no customs delays. Every SS 31 buy order includes the batch number on the packing slip for COA lookup, and each batch is tested before it goes on sale. When you buy SS-31 peptide for a larger lab order, contact [CONFIRM: email]; an SS-31 peptide buy of several vials can be supplied from a single batch on request [CONFIRM].

Scientific References and Published Studies

Key published studies on the SS-31 peptide cited on this page:

1. Zhao K, Zhao GM, Wu D, Soong Y, Birk AV, Schiller PW, Szeto HH. Cell-permeable peptide antioxidants targeted to inner mitochondrial membrane inhibit mitochondrial swelling, oxidative cell death, and reperfusion injury. J Biol Chem. 2004;279(33):34682–34690. [VERIFY pages]
2. Birk AV, Liu S, Soong Y, Mills W, Singh P, Warren JD, Seshan SV, Pardee JD, Szeto HH. The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin. J Am Soc Nephrol. 2013;24(8):1250–1261. doi:10.1681/ASN.2012121216
3. Lee C, Zeng J, Drew BG, et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab. 2015;21(3):443–454. doi:10.1016/j.cmet.2015.02.009
4. Gibson CM, Giugliano RP, Kloner RA, et al. EMBRACE STEMI study: a Phase 2a trial to evaluate the safety, tolerability, and efficacy of intravenous MTP-131 on reperfusion injury in patients undergoing primary percutaneous coronary intervention. Eur Heart J. 2016;37(16):1296–1303.
5. Mitchell W, Ng EA, Tamucci JD, et al. The mitochondria-targeted peptide SS-31 binds lipid bilayers and modulates surface electrostatics as a key component of its mechanism of action. J Biol Chem. 2020;295(21):7452–7469. doi:10.1074/jbc.RA119.012094 [VERIFY author list]
6. Hornby B, Thompson WR, Almuqbil M, et al. Natural history comparison study to assess the efficacy of elamipretide in patients with Barth syndrome. Orphanet J Rare Dis. 2022;17:336. doi:10.1186/s13023-022-02469-5
7. Karaa A, et al. Efficacy and safety of elamipretide in individuals with primary mitochondrial myopathy: the MMPOWER-3 randomized clinical trial. Neurology. 2023;101(3):e238–e252. doi:10.1212/WNL.0000000000207402 [VERIFY author list]
8. US Food and Drug Administration. FDA grants accelerated approval for first treatment for Barth syndrome. Press announcement, 19 September 2025.
9. World Anti-Doping Agency. Prohibited List 2026.

[CHECK: add DOI or PubMed links before publishing]

Related Research Peptides and Buying Guides

SS31 peptides are often studied alongside other compounds used in mitochondrial and ageing-biology research. Related products:

• NAD+ vial: the coenzyme at the centre of mitochondrial energy metabolism, as a lyophilised research vial. [LINK: NAD+ vial]
• NAD+ 1000mg research pen: NAD+ supplied pre-mixed. [LINK: NAD+ pen]
• Epitalon 10mg vial: a short synthetic peptide studied in ageing-biology models. [LINK: Epitalon vial]
• MOTS-c: the mitochondrial-derived peptide compared above. [LINK: MOTS-c vial, if stocked; otherwise delete]
• Bacteriostatic water 10ml: for reconstituting lyophilised peptides in research protocols. [LINK: Bac water]
• Guides: [LINK: How to read a peptide COA] · [LINK: How to store research peptides]

Or return to the top of this page to order SS31 10mg.

All products are for laboratory research use only. Not for human or veterinary use.