MTP-131 is a name that sends people in circles. A researcher finds a paper about a compound called MTP-131, goes looking for somewhere to buy it, and finds almost nothing. Or they find it listed next to SS-31 and elamipretide at three different prices and assume they are three different things. They are not. It is one molecule that has been renamed more often than most people change jobs.
We field this question so regularly that it seemed worth writing the whole thing down once. Here is where each name came from, when it was used, and how to make sure a literature search or a purchase order is pointing at the right compound.
Table of Contents
Table of Contents
The short answer on MTP-131
MTP-131 is the development code that Stealth Peptides, later Stealth BioTherapeutics, gave to the tetrapeptide D-Arg-Dmt-Lys-Phe-NH2. The same molecule is also called:
- SS-31, its original laboratory name.
- Bendavia, an early brand name used in clinical trials.
- Elamipretide, the official international non-proprietary name.
- Ocuvia, used for an eye-drop formulation.
- Forzinity, the brand name of the pharmaceutical product approved in 2025.
Six labels if you count the last. One structure. One CAS number, 736992-21-5. One molecular weight, 639.8 g/mol.
If you remember nothing else from this page, remember the CAS number. Names drift. The registry number does not.
Name 1: SS-31, where it started
The compound was first described in the early 2000s by Hazel Szeto in New York and Peter Schiller in Montreal. They had made a series of small peptides and numbered them. SS for Szeto and Schiller, 31 for its position in the list.
Papers from the academic labs, especially from Szeto's own group and her collaborators, have used SS-31 throughout, right up to the present. If you are reading basic science on mechanism, on cardiolipin binding or on ageing in mice, this is the name you will mostly see.
It is also the name the research supply trade uses. That is why our own product page is headed SS-31 peptide and not MTP-131. More on the origins is in our essential facts about SS-31.
Name 2: MTP-131, the company code
When a company licenses a compound, it gives it an internal code. Codes are neutral, they do not presume a brand, and they let the company talk about a programme before any official name exists.
Stealth Peptides was founded in 2006 to develop the Szeto-Schiller compounds. MTP is generally read as mitochondria-targeted peptide. The number has no special meaning that we know of.
MTP-131 shows up in the literature from roughly 2010 onward, mainly in three kinds of document. Company-sponsored preclinical studies. Conference abstracts. And clinical trial registrations, where a code is often used because the generic name has not yet been assigned.
A few examples of work published under or alongside this code:
- Studies in rats showing protection of the kidney after blood flow was cut off and restored.
- Studies in mice with heart muscle disease driven by high blood pressure hormones.
- A study in dogs with advanced heart failure, where three months of treatment improved heart function and mitochondrial measures.
- Early human pharmacology studies in healthy volunteers.
You will sometimes see it written MTP131 with no hyphen. Same thing. We look at the mechanism work under that spelling in our article on MTP131 and cardiolipin.
Name 3: Bendavia, the brand that did not last
For its first clinical programme, in heart attack patients, the company used the brand name Bendavia. The trial was EMBRACE STEMI, and the published report refers to the drug as Bendavia and as MTP-131 in the same breath.
The name was used for a few years across cardiac and kidney trials and then quietly retired. Brand names chosen early in development often are. If you come across Bendavia in a paper from around 2012 to 2016, you are reading about the same compound.
Name 4: Elamipretide, the official one
Every drug that reaches a certain stage is given an international non-proprietary name by the World Health Organization, with a matching United States Adopted Name. These are the generic names, the ones that do not belong to any company.
The name assigned was elamipretide. The ending, -tide, marks it as a peptide. From about 2016, trial reports and reviews switched to it, and it is now the standard term in clinical writing. Our article on elamipretide tells the clinical story under that name, including the trials that did not work.
A search for the generic name alone will miss most of the earlier work. That is the trap.
Name 5: Ocuvia and Forzinity
Ocuvia was a topical eye formulation tested in early trials for eye diseases. Later eye studies used injections under the skin and dropped the separate name.
Forzinity is the brand name under which a pharmaceutical form received accelerated approval from the US Food and Drug Administration in September 2025 for Barth syndrome. Details are in the FDA trial snapshot. That is a prescription medicine. It has nothing to do with research-grade material other than sharing the same active molecule.
Why the names matter when you search
Here is a test you can try. Go to PubMed and search for elamipretide. Note the number of results. Then search for SS-31. Then MTP-131. Then Bendavia. The four lists overlap but none contains all of the others.
Databases have got better at linking synonyms, but they are not perfect, and older records were indexed under whatever term the authors used. If you search one name, you will miss papers.
The fix is to search them all at once. In PubMed:
- elamipretide OR SS-31 OR MTP-131 OR Bendavia
You can run that combined search here. For trial records, the same approach works on ClinicalTrials.gov, which lists registered studies under several of the names.
Two more tips. Put SS-31 in quotation marks, or the search engine may split it at the hyphen and return every paper that mentions SS and 31. And watch out for SS-20 and SS-02, which are sister compounds, not synonyms. We explain those in our guide to the Szeto-Schiller peptide family.
Why the names matter when you buy
This is where confusion costs money.
A supplier that lists MTP-131, SS-31 and elamipretide as three separate catalogue items, with three prices, is either padding the catalogue or does not understand the product. Neither is reassuring. One compound should have one listing, with the other names given as synonyms.
When you place an order, name the compound and give the CAS number. If the supplier's paperwork shows a different CAS number, stop. If the Certificate of Analysis gives a molecular weight other than 639.8 for the free base, stop. Those two checks catch almost every mix-up.
Also check the sequence on the COA. It should read D-Arg-Dmt-Lys-Phe-NH2. There is a sister compound, SS-20, with the sequence Phe-D-Arg-Phe-Lys-NH2 and a different mass. It is a legitimate research compound in its own right, often used as a control, but it is not what you want if you ordered MTP-131.
What the MTP-131 literature actually showed
Since you may have arrived here from a paper, a quick map of the preclinical work published under this name is useful. We are summarising, not endorsing. Read the originals.
Kidney
In rat models, giving the compound before or shortly after a period of interrupted blood flow preserved the structure of mitochondria in kidney tubule cells and sped up recovery of ATP. Later studies looked at longer-term scarring. This body of work is where the cardiolipin mechanism was first laid out clearly, in 2013.
Heart
Mouse studies looked at heart enlargement and failure caused by angiotensin and by pressure overload. The dog study is the one most often cited: animals with heart failure induced by repeated tiny blockages of the coronary vessels were treated for three months and showed better pumping function, along with improved mitochondrial respiration in heart tissue.
Skeletal muscle
In aged mice, a single treatment was reported to restore mitochondrial energy output in leg muscle toward that of young animals within an hour, with improved fatigue resistance after a week. This 2013 paper is probably the most quoted one in the ageing field.
Eye and brain
Smaller numbers of studies looked at retinal cells under oxidative stress and at models of neurodegeneration.
What ties these together is that the compound seems to do most in mitochondria that are already under stress and least in healthy ones. That is a useful thing to know when choosing controls. There is more on study design in our piece on Szeto Schiller 31 research models.
From animals to people: where MTP-131 fell short
It would be misleading to stop at the animal data. The first large human trial, in heart attack patients, did not reduce the size of the damaged area. A four-week trial in heart failure did not improve heart dimensions. A Phase 3 trial in mitochondrial muscle disease missed both main endpoints.
The one clear clinical success came in Barth syndrome, a rare genetic disease of cardiolipin remodelling, and only after long-term follow-up.
For laboratory researchers, the gap between animal and human results is not a reason to dismiss the compound. It is a reason to design carefully, treat for long enough, and measure more than one thing.
How we label it
On our site and on our vials, the compound is called SS-31, with elamipretide given as the synonym. The Certificate of Analysis states the sequence, the molecular weight and the lot number. If your purchasing system or your paperwork needs it described as MTP-131, tell us and we will add that to the documents. It is a common request from institutions whose protocols were written around a particular paper.
We stock it in four grades.
- Standard Grade, from 5 mg, 98 percent or better.
- High Purity Grade, for routine cell work.
- Ultra-Pure Research Grade, 99.5 percent or better, verified by HPLC and mass spectrometry.
- Bulk Research Grade, in 100 mg, 250 mg and 500 mg vials.
If you are not sure which fits, our SS31 buying guide walks through the choice.
Ordering MTP-131 for research
We are a wholesale supplier. The minimum order is 50 units, mixed grades and sizes allowed, and other compounds in our catalogue count toward it. Those are BPC-157, GHK-Cu, Retatrutide and TB-500.
The process:
- Open the SS-31 peptide page and press Order beside the size you want.
- Enter the number of units and your delivery address.
- Choose a payment method: Apple Pay, Zelle, Chime, Cash App, USDT or Bitcoin.
- We reply by email, usually within the day, with the total and payment details.
Every order ships with the COA for its lot. If you want to see it first, ask in the message box or through the contact page.
All material is sold for laboratory and in-vitro research only. It is not for human or animal use, and we do not give advice on dosing.
Reading an older paper: a translation guide
If you have a paper open that uses MTP-131 and you want to connect it to something more recent, these pointers help.
Check the sequence. Somewhere in the methods, usually the first paragraph, the authors will give it. If it says D-Arg-Dmt-Lys-Phe-NH2, or D-Arg-2,6-dimethyltyrosine-Lys-Phe-NH2, you are reading about the same compound sold today as SS-31.
Check the supplier line. Papers from this period often say the material was provided by Stealth Peptides or Stealth BioTherapeutics. That confirms it is the company's own MTP-131 and not a look-alike.
Check how it was given. Company-sponsored animal studies generally used injection under the skin or infusion into a vein. Academic studies more often used injection into the abdomen or delivery by a small implanted pump. The route affects how results compare.
Check the units. Some papers give doses by weight of the salt, some by weight of the free peptide, and many do not say which. When two studies of MTP-131 seem to disagree on dose, this is often the reason.
Check the date against the trial history. A preclinical paper from 2012 was written when hopes were high and no large trial had reported. A paper from 2020 was written with the knowledge that several had missed. The tone of the discussion sections changes accordingly, and it is worth reading both with that in mind.
How to refer to the compound in your own work
If you are writing up research, you have to choose a name. Our suggestion, for what it is worth:
In a basic science paper, use SS-31 at first mention and give the alternatives in brackets: SS-31, also known as elamipretide and MTP-131. Then use SS-31 throughout. That matches the mechanistic literature your readers will know.
In a clinical or translational paper, lead with elamipretide and give SS-31 and MTP-131 as synonyms.
In either case, state the sequence, the CAS number and the supplier, grade and lot in the methods. It takes two lines and removes all doubt. Reviewers increasingly ask for it, and readers trying to repeat your work will thank you.
Put all the names in your keywords. Someone searching in five years may use any of them, and you want to be found.
Other codes you might run into
A few more labels turn up around MTP-131 and cause confusion.
SBT numbers. The same company later used an SBT prefix for other compounds in its pipeline. Those are different molecules, some of them newer relatives designed to improve on the original. A paper about an SBT compound is not about this one unless it says so.
SS-20. A sister peptide, not a synonym. It lacks the dimethyltyrosine and is mainly used as a control.
SS-02. Another relative, with strong opioid activity. Definitely not interchangeable.
MTP-101, MTP-151 and similar. You may occasionally see other MTP numbers in old abstracts or patents. They refer to other candidates from the same programme.
Brand names on supplement sites. Now and then a product appears with a name that sounds related and a label hinting at mitochondria. Unless the sequence and CAS number are stated and match, treat it as unrelated.
The rule is the same every time. Names are marketing, history or habit. The sequence and the registry number are chemistry. When in doubt, go back to those.
Why we care about getting this right
It might seem like a lot of words about labels. Here is why it matters to us. Every month we hear from someone who bought what they thought was MTP-131 elsewhere, could not match it to the paper they were following, and lost weeks working out whether the fault was in the compound or the experiment. Almost always the compound was fine and the confusion was in the naming. Ten minutes with the CAS number would have saved them.
A short history of how drug codes work
It may help to know that MTP-131 is a typical example of a wider habit, not an oddity. Almost every drug candidate goes through the same sequence of labels.
First comes a laboratory name, chosen by the scientists. It might be initials and a number, as here, or a compound number from a screening library. It appears in the early academic papers and tends to stick among researchers.
Next comes a company code, once someone licenses the molecule. Two to four letters for the company or programme and a number. Codes are deliberately bland. They do not promise anything, they are easy to trademark around, and they let a company discuss a programme before any generic name exists. MTP-131 belongs to this stage.
Then a brand name may be tried out for trials, and may or may not survive to market.
Then an official generic name is assigned, built from standard stems that tell pharmacists what class the drug belongs to.
Finally, if the drug is approved, a marketed brand name goes on the box.
So a molecule that reaches the pharmacy commonly has four or five names by the time it gets there. The research supply trade usually settles on the first, the laboratory name, because that is what the people ordering it read in the papers. This is why you will find SS-31 on a supplier's price list and MTP-131 in a trial registry, and why knowing the full set of names is part of knowing the compound.
What we check when a customer asks for MTP-131 by name
When an enquiry comes in asking for MTP-131, we do three things before quoting. We confirm with the customer that they mean the tetrapeptide with CAS number 736992-21-5. We ask which paper or protocol they are following, because that often tells us which grade suits them. And we note on the order that the documents should carry MTP-131 as a synonym, so that the paperwork matches what their records expect. It adds a few minutes and avoids confusion later.
Questions we hear about MTP-131
Is MTP-131 the same as SS-31?
Yes. MTP-131 is the company development code for the compound first published as SS-31.
Is MTP-131 the same as elamipretide?
Yes. Elamipretide is the generic name assigned later to the same molecule.
Why can I not find MTP-131 for sale under that name?
Because research suppliers almost all list it as SS-31. Search for that, and confirm with the CAS number 736992-21-5.
What does MTP stand for?
It is generally taken to mean mitochondria-targeted peptide. It was a company code, not a scientific term.
Is MTP-131 different from MTP131?
No. The hyphen is a matter of style. Some papers and databases drop it.
How should I store it?
Dry, at minus 20, in the dark. Our SS-31 peptide storage guide has the full routine.
Summing up
One molecule, several names, picked up at different stages of a long development. SS-31 in the academic lab. MTP-131 inside the company. Bendavia in the first trials. Elamipretide as the official generic. Forzinity on the pharmacy label.
Search with all of them. Buy by CAS number. Check the sequence and the mass on the certificate. And if a seller tries to charge you three prices for three names, you know what to do.
For a neutral overview of the compound, the Wikipedia article on elamipretide is a reasonable starting point. For current sizes and prices, see our SS-31 peptide page.