SS-31 for Sale: How to Evaluate a Vendor Before You Buy
SS-31 is a mitochondria-targeting tetrapeptide with a growing preclinical research record. Finding a vendor worth trusting takes more than a Google search.
SS-31 (also called Elamipretide or MTP-131) is sold as a research compound by several peptide vendors, but quality varies widely. A legitimate vendor will supply a third-party certificate of analysis showing purity above 98%, confirm testing by an independent HPLC and mass spectrometry lab, and clearly label the product for research use only. No vendor-sold SS-31 is FDA approved; the only clinical-stage form is Elamipretide, which has been studied in sponsored trials but has not received FDA approval as of this writing.
What Is SS-31 and Why Does the Research Community Care About It?
SS-31 is a synthetic tetrapeptide with the sequence D-Arg-2'6'-dimethylTyr-Lys-Phe-NH2. It belongs to the Szeto-Schiller family of mitochondria-targeted peptides, developed in the early 2000s by researchers Hazel Szeto and Peter Schiller. The compound is designed to concentrate in the inner mitochondrial membrane, where it interacts with cardiolipin, a phospholipid critical to the electron transport chain.
Preclinical interest in SS-31 centers on its potential to reduce mitochondrial oxidative stress and support ATP production in models of ischemia-reperfusion injury, heart failure, and age-related muscle decline. A 2020 study published in GeroScience (Whitson et al., n=14 older adults) examined skeletal muscle mitochondrial function after Elamipretide administration and reported improvements in mitochondrial energetics, though the sample size was small and the findings are preliminary. Most of the mechanistic evidence remains in rodent and cell models.
The commercial name Elamipretide, also called MTP-131, refers to the same compound. Stealth BioTherapeutics held the primary clinical development program. That company filed for bankruptcy in 2023, which has created uncertainty about the compound's clinical future. Researchers sourcing SS-31 for laboratory work should understand this context before evaluating vendor claims.
What Does a Legitimate SS-31 Vendor Actually Look Like?
The single most important document a vendor can provide is a certificate of analysis from a third-party laboratory, not an in-house test. A credible COA will name the testing facility, list the analytical methods used (typically high-performance liquid chromatography for purity and mass spectrometry for molecular identity confirmation), state the purity percentage, and carry a lot number that matches the product you are ordering. Purity below 98% on a research-grade peptide is a meaningful concern; many reputable vendors target 99% or higher.
Beyond the COA itself, check whether the vendor publishes the name of the testing lab and whether that lab is independently verifiable. Some vendors use in-house HPLC and call it third-party testing; that is not the same thing. A vendor willing to share the lab's name and the raw chromatogram data is demonstrating a level of transparency that distinguishes it from competitors who post a generic certificate with no traceable origin.
Labeling matters too. A compliant vendor will mark SS-31 products clearly as 'for research use only' and 'not for human consumption.' This is not just legal boilerplate. It signals that the vendor understands the regulatory category of the product. Vendors who imply clinical or personal-use applications in their marketing copy are either uninformed about the rules or indifferent to them, neither of which is a good sign for quality control.
Red Flags That Should Stop a Purchase
Price is a useful signal. SS-31 is a tetrapeptide with a non-standard amino acid (the dimethyltyrosine residue), which makes synthesis more complex than a simple linear peptide. Vendors pricing SS-31 dramatically below market norms are either cutting corners on synthesis, skipping quality testing, or selling a mislabeled or underdosed product. That does not mean the most expensive option is automatically the best, but suspiciously low prices warrant scrutiny.
Absence of a returnable COA is a hard stop. If a vendor's website shows a sample certificate but does not provide a lot-specific document for the actual product being shipped, there is no way to verify what is in the vial. Some vendors will provide COAs on request before purchase; that is a reasonable practice. Vendors who refuse or who provide only a generic document should be avoided.
Marketing language that implies medical benefit, disease treatment, or personal health outcomes is a regulatory red flag and a credibility problem. SS-31 has not been approved by the FDA in any form. Elamipretide did reach Phase 2 and Phase 3 clinical trials for conditions including Barth syndrome and heart failure with preserved ejection fraction, but those trials did not result in an approved drug. A vendor claiming their SS-31 'treats' or 'reverses' any condition is making an unsupported and legally problematic claim.
How to Read an SS-31 Certificate of Analysis
An SS-31 COA should confirm the molecular formula C32H49N9O5 and a molecular weight of approximately 639.8 g/mol. If the mass spectrometry result on the COA does not match this, the product is either mislabeled or contaminated. This is a basic check any researcher can perform before placing an order, and it takes about 30 seconds.
HPLC purity is reported as a percentage of the main peak area relative to total peak area. A single clean peak with minimal shoulders or secondary peaks is what a well-synthesized peptide looks like. Multiple peaks or a broad main peak suggest impurities, incomplete synthesis, or degradation. Some COAs also report water content by Karl Fischer titration; this matters because lyophilized peptides can absorb moisture, which affects the actual peptide content per milligram.
Endotoxin testing is worth asking about specifically for any peptide intended for cell culture or animal research. Bacterial endotoxins are a common contaminant in peptide synthesis and can confound experimental results. Not every vendor tests for endotoxins, but those who do, and who publish the results, are operating at a higher standard. Ask before ordering if this matters for your research application.
Storage, Shipping, and What Vendors Owe You in Writing
SS-31 in lyophilized form is relatively stable at room temperature for short periods, but long-term storage is typically recommended at -20°C or colder to preserve peptide integrity. A vendor's shipping practices should reflect this. Cold-pack shipping for lyophilized peptides is a reasonable expectation, particularly for orders traveling long distances or during warm months. Vendors who ship peptides in standard envelopes with no temperature control are cutting corners that affect product quality on arrival.
Return and replacement policies tell you a great deal about a vendor's confidence in their product. A vendor who offers no recourse if a product arrives damaged, fails an independent purity test, or is clearly mislabeled is transferring all the risk to the buyer. Look for explicit written policies on the vendor's website, not just a customer service email address. The policy should specify what documentation is needed to initiate a return or replacement and what the resolution timeline looks like.
Payment and privacy practices are also worth reviewing. Vendors who accept only cryptocurrency with no buyer protection, who collect excessive personal data, or who have no clear privacy policy are operating in ways that create additional risk for buyers. This does not automatically mean their peptides are low quality, but it does suggest the business is not structured for accountability, which matters when something goes wrong.
Vetted vendors for research use
Our index screens vendor documentation against the checks in this review. We never accept payment for rank placement.
Frequently asked questions
Is SS-31 the same compound as Elamipretide?
Yes. SS-31, Elamipretide, and MTP-131 all refer to the same tetrapeptide with the sequence D-Arg-2'6'-dimethylTyr-Lys-Phe-NH2. Elamipretide is the INN (International Nonproprietary Name) used in clinical trial documentation. Stealth BioTherapeutics conducted Phase 2 and Phase 3 trials under that name before the company filed for bankruptcy in 2023. Vendor-sold SS-31 is not the same as a pharmaceutical product and has not received FDA approval in any form.
What purity level should a research-grade SS-31 product show on its COA?
Most reputable research-compound vendors target 98% purity or higher by HPLC for peptides sold for laboratory use. Some vendors specify 99% or greater. The COA should come from a named third-party laboratory, include the lot number matching the product, and show the actual chromatogram or at minimum the peak area percentage. A COA that lists only a round number like '98%' with no supporting analytical data and no lab name is not a reliable document.
What does the published human research on SS-31 actually show?
Human research on SS-31 (Elamipretide) is limited and mostly early-phase. A 2020 GeroScience study by Whitson et al. enrolled 14 older adults and reported improvements in skeletal muscle mitochondrial energetics after Elamipretide administration, but the small sample size limits conclusions. Phase 3 trials in Barth syndrome and heart failure with preserved ejection fraction were conducted but did not result in FDA approval. The bulk of mechanistic evidence comes from animal and cell studies, which cannot be directly extrapolated to human outcomes.
Sources
Sources are listed most recent first. Cited studies are peer-reviewed unless noted.
- Whitson et al., 2020, GeroScience - Elamipretide and skeletal muscle mitochondria in older adults Small human study on mitochondrial energetics
- Szeto, 2014, Phytochemistry Reviews - SS peptide mechanism and cardiolipin interaction Foundational mechanistic review of SS peptides
- Daubert et al., 2017, JACC: Basic to Translational Science - Elamipretide Phase 2 heart failure trial Phase 2 human trial data for cardiac application
Educational and informational content only. This is not medical advice, diagnosis, or treatment. The compounds discussed are research compounds not approved by the FDA or any equivalent authority for human use outside prescribed contexts. Always consult a licensed clinician before any health decision.
