SS-31 (1 Vial)

Description

Buy SS-31 — a mitochondria-targeted antioxidant tetrapeptide synthesized in US-based facilities and available from PSPeptides in 10mg lyophilized vials. SS-31, also known as Elamipretide or MTP-131, is one of the most rigorously studied mitochondria-protective peptides in modern preclinical research. When researchers buy SS-31, they are acquiring a compound with an expanding body of peer-reviewed literature behind it — spanning cardiac function, neurodegenerative disease, ischemia-reperfusion injury, aging, and skeletal muscle preservation.

What Is SS-31?

SS-31 is a synthetic tetrapeptide with the amino acid sequence D-Arg-dimethylTyr-Lys-Phe-NH₂. It was originally developed by Hazel Szeto and Peter Schiller — hence the “SS” designation — as part of a class of aromatic-cationic peptides designed to selectively concentrate within the inner mitochondrial membrane. This targeting is achieved through the peptide’s alternating cationic and aromatic residues, which give it a high affinity for cardiolipin, the phospholipid that anchors cytochrome c to the inner mitochondrial membrane.

Cardiolipin plays a critical structural and functional role in the mitochondrial electron transport chain (ETC). When cardiolipin becomes peroxidized under oxidative stress conditions, cytochrome c detaches from the membrane and can trigger apoptosis while simultaneously impairing ATP synthesis. SS-31 works by binding directly to cardiolipin, stabilizing its interaction with cytochrome c, scavenging reactive oxygen species (ROS) at the source, and restoring electron transport efficiency. Unlike conventional antioxidants that act in the cytoplasm, SS-31 concentrates approximately 1,000-fold in the mitochondria relative to cytosol, making it uniquely effective at the site of ROS generation.

Researchers who buy SS-31 for preclinical studies frequently cite this mitochondrial targeting mechanism as the key reason for the compound’s exceptional potency in animal models at nanomolar to picomolar concentrations. The original characterization of SS-31’s cardiolipin-binding mechanism is well documented in peer-reviewed literature — see the foundational PubMed research on SS-31 and cardiolipin peroxidation. For a comprehensive overview of peptide research, see our complete guide to peptides.

Buy SS-31: Key Research Applications

The research literature for SS-31 spans multiple disease models and organ systems. Below are the primary areas where investigators choose to buy SS-31 for ongoing preclinical work:

• Cardiac Ischemia-Reperfusion Injury: SS-31 has been extensively studied in myocardial ischemia-reperfusion (I/R) models. Multiple rodent studies have demonstrated that SS-31 administration prior to reperfusion significantly reduces infarct size, preserves left ventricular ejection fraction, and limits cardiomyocyte death. The mechanism involves SS-31’s ability to prevent the mitochondrial permeability transition pore (mPTP) from opening — a key driver of reperfusion-phase cell death. Researchers who buy SS-31 for cardiac research often use it as a reference compound in mPTP inhibition studies.
• Heart Failure with Preserved Ejection Fraction (HFpEF): SS-31 (under the clinical name Elamipretide / MTP-131) has been investigated in human clinical trials for HFpEF, a form of heart failure characterized by diastolic dysfunction rather than reduced ejection fraction. Phase II SPAR trial data demonstrated improvements in exercise tolerance and cardiac structure in HFpEF patients treated with subcutaneous SS-31 infusions. Investigators exploring this area frequently buy SS-31 to model diastolic dysfunction in aged or hypertensive rodent models.
• Neurodegenerative Disease Models: Mitochondrial dysfunction is a hallmark of Alzheimer’s disease, Parkinson’s disease, and ALS. SS-31 has shown neuroprotective effects in transgenic AD mouse models by reducing amyloid-beta-induced oxidative stress, preserving synaptic mitochondria, and improving spatial memory in Morris water maze tests. Researchers working in neurodegeneration buy SS-31 for its ability to cross the blood-brain barrier at low doses and directly protect neuronal mitochondria.
• Skeletal Muscle Aging (Sarcopenia): Mitochondrial dysfunction in skeletal muscle is a primary driver of age-related muscle loss. SS-31 treatment in aged mouse models has been shown to restore mitochondrial morphology, improve muscle fiber cross-sectional area, and enhance exercise capacity. Investigators studying sarcopenia buy SS-31 as a tool to test the mitochondrial theory of muscle aging. See our related post on peptides for muscle growth and recovery.
• Renal Ischemia and Acute Kidney Injury: SS-31 has demonstrated protective effects in models of acute kidney injury (AKI) induced by ischemia, cisplatin nephrotoxicity, and contrast-induced nephropathy. Renal tubular epithelial cells are highly dependent on mitochondrial oxidative phosphorylation, making them exceptionally vulnerable to mitochondrial dysfunction. Researchers studying nephrology buy SS-31 to probe renoprotective strategies in these models.
• Retinal Degeneration: The retina has among the highest metabolic demands of any tissue and is highly sensitive to mitochondrial stress. SS-31 has been studied in models of age-related macular degeneration (AMD), retinal ischemia, and diabetic retinopathy, where it has demonstrated preservation of retinal ganglion cells and photoreceptor function. Ophthalmology researchers buy SS-31 for its unique ability to target retinal mitochondria via intravitreal or systemic administration.
• Mitochondrial Biogenesis and Aging: Beyond acute protection, SS-31 has been shown to upregulate PGC-1α expression and promote mitochondrial biogenesis in aged tissues, suggesting a role beyond just antioxidant protection. Longevity researchers and those studying aging biology buy SS-31 to explore mitochondria-targeted interventions in healthspan extension models. For more context, see our guide on best peptides for longevity and anti-aging.

Product Specifications

Certificate of Analysis

Every vial of SS-31 sold by PSPeptides is backed by a batch-specific Certificate of Analysis (COA) performed by an independent third-party laboratory. The COA confirms identity, purity (≥99% by HPLC), and molecular weight (by mass spectrometry). Researchers who buy SS-31 from PSPeptides can request their batch COA at any time by contacting support with their order number. Understanding how to read a peptide COA is essential for research quality control — see our guide: how to read a peptide certificate of analysis.

Reconstitution & Handling

SS-31 is supplied as a lyophilized powder and must be reconstituted before use in aqueous-based assay systems. The compound is highly water-soluble due to its cationic character. To reconstitute, add sterile water or bacteriostatic water slowly to the vial, gently swirl (do not shake), and allow the powder to fully dissolve. A common reconstitution approach is to add 1 mL of sterile water to yield a 10 mg/mL stock solution, which can then be diluted further for working concentrations.

Reconstituted SS-31 should be stored at 2–8°C and used within 28 days. For long-term storage, divide reconstituted solution into single-use aliquots and store at −80°C to prevent freeze-thaw degradation. Lyophilized vials should be stored at −20°C and protected from moisture and light. For a complete protocol, refer to our peptide reconstitution guide and our peptide storage guide.

Frequently Asked Questions: Buy SS-31

What is the typical concentration researchers use when they buy SS-31 for in vitro work?
In cell culture studies, SS-31 is commonly used at concentrations ranging from 0.1 nM to 1 µM depending on the cell type and endpoint. Its high mitochondrial accumulation ratio means effective intracellular concentrations are achieved at sub-nanomolar extracellular doses in many models. Researchers should optimize concentration ranges in preliminary dose-response experiments.

Is SS-31 the same as Elamipretide or MTP-131?
Yes. SS-31, Elamipretide, and MTP-131 are all names for the same tetrapeptide compound (D-Arg-dimethylTyr-Lys-Phe-NH₂). “SS-31” refers to the Szeto-Schiller nomenclature used in academic literature. “MTP-131” was Stealth BioTherapeutics’ research designation. “Elamipretide” is the INN (International Nonproprietary Name) used in clinical trial contexts. When researchers buy SS-31 from PSPeptides, they receive the identical peptide sequence used across all published literature.

How does SS-31 compare to other mitochondria-targeted compounds like MitoQ or SkQ1?
Unlike MitoQ and SkQ1, which are mitochondria-targeted quinone derivatives that rely on TPP+ (triphenylphosphonium) cation for targeting, SS-31 accumulates in the inner mitochondrial membrane through its direct interaction with cardiolipin — without requiring a membrane potential gradient. This means SS-31 can protect mitochondria even when membrane potential is already compromised, a scenario common in ischemia and advanced disease states. Many investigators who buy SS-31 for comparative studies cite this as a key mechanistic distinction.

What are the stability considerations for SS-31 in solution?
Reconstituted SS-31 is stable for up to 28 days at 4°C in the absence of repeated freeze-thaw cycles. The peptide is susceptible to oxidation of the dimethyltyrosine residue under prolonged light exposure. Researchers should protect solutions from direct light and avoid storage in polypropylene tubes with surface adhesion properties, as SS-31 can adsorb to some plastics at very low concentrations. Low-bind tubes are recommended for sub-nanomolar working solutions.

Where can I buy SS-31 with verified purity for research?
PSPeptides offers buy SS-31 in 10mg lyophilized vials with ≥99% purity verified by independent HPLC and mass spectrometry. Each order includes access to a batch-specific COA. US-manufactured, fast shipping, with free UPS 2nd Day Air on orders over $200. See our guide on how to choose a research peptide supplier for a full breakdown of what to look for.

SS-31 in the Context of Mitochondrial Peptide Research

SS-31 belongs to an emerging class of mitochondria-targeted peptides that are reshaping how researchers approach oxidative stress and bioenergetic failure. Unlike upstream antioxidants such as NAC or vitamin C that act in the cytosol, SS-31 intervenes at the electron transport chain itself — the primary site of superoxide radical generation in most cell types. This has made it a benchmark compound in the field of mitochondrial medicine.

Investigators studying related mitochondrial peptides such as MOTS-c often buy SS-31 as a complementary tool to dissect different aspects of mitochondrial regulation. Where MOTS-c activates AMPK and regulates nuclear gene expression, SS-31 acts directly on the inner mitochondrial membrane to preserve structural integrity and electron flux. See our guide on MOTS-c mitochondrial peptide research for comparison. Researchers interested in longevity biology frequently buy SS-31 and MOTS-c together to probe complementary mitochondrial pathways. For a broader discussion of longevity peptides, see our best peptides for longevity and anti-aging guide.

The clinical translation of SS-31 has been more advanced than most research peptides. Phase II clinical data from the SPAR trial (NCT02814097) demonstrated that subcutaneous infusion of Elamipretide significantly improved peak VO2, six-minute walk distance, and left atrial volume index in HFpEF patients over 28 weeks. This clinical evidence base makes buy SS-31 an especially compelling choice for researchers aiming to model clinically relevant mitochondrial disease states.

Why Researchers Buy SS-31 from PSPeptides

• 99%+ Purity Guaranteed: Every batch of SS-31 is tested by an independent third-party lab via HPLC and mass spectrometry. You receive a COA confirming purity before your experiment begins. When you buy SS-31 from PSPeptides, there are no purity surprises.
• US-Manufactured: SS-31 is synthesized in a US-based, GMP-compliant peptide synthesis facility using pharmaceutical-grade reagents. We do not source from overseas manufacturers. Researchers who buy SS-31 for serious preclinical work require this level of supply chain control.
• Consistent Batch Quality: Our lot-to-lot purity variance is less than 0.5%. This consistency is critical for multi-experiment research programs where inter-batch variability can introduce confounding variables. Researchers who regularly buy SS-31 for ongoing studies rely on this reproducibility.
• Fast Shipping: Free UPS 2nd Day Air on orders over $200. Orders placed before 2 PM EST ship same-day on business days. When your lab needs to buy SS-31 for an upcoming experiment, timing matters.
• Research-Focused Support: Our team understands peptide research. Whether you have questions about reconstitution, stability, concentration selection, or study design considerations, we’re available to help researchers who buy SS-31 get the most from their experiments.
• Transparent Pricing: No hidden fees. The price you see is the price you pay. Researchers who need to buy SS-31 on a recurring basis can contact us about volume pricing for ongoing programs.

All PSPeptides products are sold exclusively for laboratory and in vitro research use. SS-31 / Elamipretide is not approved by the FDA for human use. Not intended for human consumption, veterinary use, or clinical application. For research use only.

SS-31 Mechanism: Cardiolipin Interaction in Detail

To fully appreciate why researchers buy SS-31 over conventional antioxidants, it is worth examining the cardiolipin interaction in greater biochemical detail. Cardiolipin is a unique anionic phospholipid found almost exclusively in the inner mitochondrial membrane (IMM). It consists of two phosphatidic acid units linked by a glycerol backbone, giving it four acyl chains and a distinctive bicyclic structure. Cardiolipin is not merely a structural lipid — it is functionally critical for the assembly and activity of complexes I, III, IV, and V of the electron transport chain, as well as for cytochrome c binding, cristae morphology, and the efficiency of oxidative phosphorylation.

Under conditions of oxidative stress, cardiolipin is highly susceptible to peroxidation because it is concentrated precisely where mitochondrial ROS are generated. Cardiolipin peroxidation has three downstream consequences: (1) dissociation of cytochrome c from the IMM, which impairs electron transfer from complex III to complex IV; (2) activation of cytochrome c’s peroxidase activity, leading to further cardiolipin oxidation in a positive feedback loop; and (3) opening of the mitochondrial permeability transition pore (mPTP), which triggers apoptosis and necrosis.

SS-31 interrupts all three of these processes simultaneously. Its aromatic-cationic structure allows it to intercalate into the IMM and bind directly to cardiolipin’s polar headgroup, preventing peroxidation. Simultaneously, SS-31’s dimethyltyrosine residue scavenges ROS directly. The result is preservation of cytochrome c binding, maintained ETC electron flux, and suppressed mPTP opening — a mechanistic profile that explains why researchers across multiple disease areas consistently buy SS-31 as their mitochondrial intervention of choice.

SS-31 Research Dosing Considerations

Published preclinical literature for SS-31 covers a wide range of model systems, administration routes, and concentration strategies. Researchers who buy SS-31 for in vivo work should note that the published literature uses a range of dosing strategies depending on the disease model:

• Cardiac I/R models (rodent): Intravenous administration of 3–10 mg/kg prior to reperfusion is the most commonly cited approach in infarct size reduction studies. Some studies use subcutaneous administration for chronic dosing paradigms.
• Skeletal muscle aging models: Subcutaneous injection of 3 mg/kg/day over 8 weeks has been used in aged mouse models to assess mitochondrial morphology, fiber cross-sectional area, and grip strength outcomes.
• Neurodegeneration models: Intranasal delivery has been explored as a CNS delivery strategy in some labs, while others use systemic (IP or IV) administration and rely on the peptide’s reported ability to cross an intact blood-brain barrier at sufficient doses.
• In vitro cell culture: Effective concentrations range from 0.1 nM to 1 µM. The compound’s high mitochondrial accumulation ratio means nanomolar extracellular concentrations often produce significant intracellular mitochondrial effects.

Researchers should establish their own dose-response curves in their specific model systems. PSPeptides provides SS-31 with sufficient purity and consistency to support rigorous multi-dose experiments. For questions about dosing strategy, our support team is available to point researchers toward relevant published protocols. We also recommend reviewing our guide on peptide side effects and safety considerations as part of study design planning.

How to Order: Buy SS-31 from PSPeptides

Ordering is straightforward. Select the 10mg vial option, add to cart, and proceed through checkout. PSPeptides accepts all major credit cards and PayPal. Orders over $200 qualify for free UPS 2nd Day Air shipping. Orders placed before 2 PM EST on business days ship same-day. Once shipped, you will receive tracking information via email. Our team is available via live chat and email for pre-sale questions, order inquiries, or COA requests.

Researchers at academic institutions or companies who need to buy SS-31 in larger quantities for extended programs should contact us about multi-vial pricing. We also stock a range of complementary research peptides and supplies including bacteriostatic water for reconstitution. For guidance on evaluating any peptide vendor before you buy, read our detailed breakdown: how to choose a research peptide supplier.