Peptide guide

SS-31

Elamipretide (MTP-131, Bendavia) — a mitochondria-targeting tetrapeptide studied for cellular energy and aging.

SS-31 is a lab-made peptide that homes in on mitochondria, the structures that make energy inside your cells, and it has more real human-trial exposure than almost any peptide sold this way. It ran through Phase 2 and Phase 3 studies in heart failure, mitochondrial disease, and eye disease, with mixed results, and in September 2025 its drug form was approved for one rare condition. It still isn't approved for the longevity and energy uses people buy it for, and most of that interest rests on animal and early human data. The practical questions are how to handle it and how not to get scammed buying it.

By the Zapify Research team

Reviewed against 9 clinical & research sources · Updated June 2026 · Educational use only

Type: Tetrapeptidemito-targeting
Route: Subcutaneous
Typical dose: ~40 mg/dayreported in trials
Cycle: Daily, ongoingin studies
Storage: Mixed: 2–4 wksSealed: months
Status: Approved for one rare disease only

What is SS-31?

A four-amino-acid mitochondria-targeting peptide (elamipretide) that binds cardiolipin; FDA-approved in September 2025 only for the rare Barth syndrome.

SS-31 is a peptide, a short chain of amino acids, the building blocks that make up every protein in your body. This one is only four units long, with the sequence D-Arg-Dmt-Lys-Phe-NH2. The name comes from the Szeto-Schiller series it belongs to, after the two researchers at Weill Cornell who developed it. You'll also see it called elamipretide, MTP-131, or Bendavia.

What sets it apart from most peptides sold this way is where it goes. SS-31 is built to concentrate inside mitochondria, the structures that turn food and oxygen into usable energy in nearly every cell. It carries a positive charge that pulls it toward cardiolipin, a lipid that lines the inner mitochondrial membrane. By binding there, it appears to help that membrane keep its shape and run its energy machinery cleanly. That targeting is the whole point of the molecule, and it's why the research has leaned toward tissues that burn the most energy: heart, muscle, nerve, and eye.

SS-31 also stands apart on evidence. Unlike most compounds in this category, it has been through multiple Phase 2 and Phase 3 human trials, and its drug form crossed the regulatory finish line in 2025. But that approval is narrow, and the gap between what it's approved for and what it's sold for is wide.

In September 2025 the FDA granted accelerated approval to elamipretide, under the brand name Forzinity, for Barth syndrome, a rare inherited mitochondrial disorder, to improve muscle strength in patients weighing at least 30 kg. That is the only approved use. SS-31 is not approved for longevity, anti-aging, energy, or general performance, which are the reasons most people buy it. For those uses it remains an experimental research compound.

What is it studied for?

It cleared multiple Phase 2 and 3 human trials with mixed results, reaching approval for one rare disease while larger heart, muscle, and eye trials missed.

SS-31 has a deeper human record than most peptides in this market, and that's the honest headline. It has been through several completed clinical trials, not just animal work. The results were mixed: a single rare-disease program reached approval, while larger trials in heart failure, mitochondrial myopathy, and dry macular degeneration missed their main goals. So the evidence is real and substantial, and it is also genuinely inconclusive for most of what people hope it does.

Evidence base, by subject

Multiple Phase 2–3Human clinical trials

1 (Barth syndrome)Approved human uses

The research has clustered around energy-hungry tissue:

Heart & muscleHeart failure and primary mitochondrial myopathy. The Barth syndrome program, which reached approval, sits here too, measured by muscle strength.

Eye & retinaDry age-related macular degeneration, where the retina's high energy demand made it a candidate. A Phase 3 study, ReNEW, is ongoing.

Aging & cellular energyMitochondrial decline with age is the rationale behind the longevity interest. This is mostly animal and mechanism work, not finished human trials for that use.

The mechanism is unusually well characterized for a peptide of this kind. SS-31 binds cardiolipin, stabilizes the folded membrane structures where energy is produced, supports ATP output, and lowers the reactive oxygen species that damage mitochondria over time. That part is solid in the lab. What's still open is whether stabilizing mitochondria translates into the outcomes people want, which is exactly where the bigger trials came up short.

Why people use it

People chase energy, recovery, and longevity, but no trial shows it delivers those and several large studies missed their primary endpoints.

Most people who try SS-31 are chasing something tied to cellular energy. These are the reasons they reach for it, not evidence that it delivers:

Age-related fatigue and the sense of declining stamina, framed around mitochondria slowing down over time.
Recovery and endurance, on the theory that cleaner mitochondrial function means more usable energy under load.
Heart, muscle, or metabolic concerns, drawn from the trial programs in those tissues.
Interest in the longevity space, where mitochondrial health is a recurring target and SS-31 is one of the better-studied options.

No trial has shown SS-31 will deliver the energy or longevity benefits it's marketed for, and several large studies in other conditions missed their primary endpoints. What's there is a clear, well-understood mechanism, more completed human safety data than almost any peptide in this category, and one approved rare-disease use. That's a stronger foundation than most compounds here can claim. It still isn't proof for the everyday uses people want, and it won't substitute for the basics that do have evidence: sleep, training, and metabolic health.

How to reconstitute SS-31

Mix gently with bacteriostatic water; a 50 mg vial in 2 mL gives 25 mg/mL, so 40 units on a U-100 syringe is 10 mg.

Research vials of SS-31 arrive as a dry powder. Before use, it's mixed into a liquid, a step called reconstitution. It's the same process used for most injectable peptides, and it's simpler than it looks.

Step 1Start with powderWipe the rubber stopper with an alcohol swab.

Step 2Add bac. waterRun it slowly down the inside wall — never shake.

Step 3Draw your doseThe calculator gives the exact units to draw to.

Wipe the rubber stopper with an alcohol swab first, every time.
Use bacteriostatic water, not plain sterile water and not saline. The trace of benzyl alcohol in it holds back bacteria, which matters because you'll be drawing from the same vial across days.
Add the water slowly, running it down the inside glass wall. Don't blast it straight onto the powder.
Don't shake it. Swirl gently and let it dissolve on its own. Shaking foams the solution and can damage the peptide.

A common research setup is a 50 mg vial mixed with 2 mL of bacteriostatic water, which gives 25 mg/mL. On a U-100 insulin syringe, 40 units would then be 10 mg. The water doesn't change how much peptide is in the vial; it only sets the concentration, which decides how many units you draw. More water means a more dilute mix and a bigger draw for the same dose. You can't ruin it with too much or too little, you only change the draw math, and that's what the calculator handles.

Calculate your exact SS-31 reconstitution →

Dose & units

No self-dose is approved beyond Barth syndrome; trials studied 40 mg once daily under the skin, rotating injection sites, run continuously rather than cycled.

The only FDA-approved dose for elamipretide is for Barth syndrome, set and supervised by a prescriber. There is no approved self-dose for longevity, energy, or any of the off-label uses. Everything below is what the clinical trials and clinics report, not a medical standard. Decide what goes into your body with a licensed provider, not with this page.

Typical range

Across the clinical programs, the dose studied most was 40 mg once a day, injected under the skin and rotated between the abdomen, thigh, and upper arm. That figure came from dose-finding trials, not from someone's protocol online, which is part of why SS-31's numbers are firmer than most peptides here.

Titration

Trials generally ran a steady daily dose rather than ramping up. People using it off-label often still begin lower and watch for injection-site reactions before settling in, since those are the most common complaint. There's no medal for starting high.

Cycling

Unlike repair peptides that run in on-and-off cycles, SS-31 was studied as a continuous daily treatment, including extension studies stretching past three years. The thinking is that mitochondrial support is maintained, not pulsed. Whether indefinite daily use makes sense outside a trial is exactly the kind of question a provider should weigh in on.

For the exact mark to draw to on your insulin syringe, don't eyeball it. The calculator turns your vial size, water, and dose into the precise number of units.

Get your exact units →

Storage

Sealed powder keeps for months at room temperature, but a reconstituted vial belongs in the fridge and should be used within 2–4 weeks.

Sealed & drySealed dry powder stays stable for months at room temperature and tolerates shipping heat before mixing.

ReconstitutedRefrigerate at 2–8 °C in the main compartment and use within about 2–4 weeks; don't freeze, keep out of light, discard if cloudy.

You'll see longer windows quoted for peptide vials. Those figures are beyond-use dates for a sealed, unmixed vial that a compounding pharmacy has stability-tested, and they stop applying the moment you add water. A mixed vial runs on the shorter clock instead, because that's how long the preservative in bacteriostatic water reliably keeps the solution clean once you're drawing from it.

That limit is about contamination, not potency — the peptide itself often stays good well beyond it. Reconstitute with plain sterile water instead of bacteriostatic and you drop to a day or two, since there's no preservative holding bacteria back.

Don't freeze a reconstituted vial, keep it out of direct light, write the mix date on the label, and throw it out if the solution ever turns cloudy or discolored, whatever the date says.

Side effects & safety

It has the cleanest trial safety record here, mostly injection-site reactions, but there's no pregnancy data and it may fall under WADA's S0 category.

SS-31 has the most reassuring safety record in this category, and that's because it was actually measured. Across multiple trials, including extension studies running well over a hundred weeks, no serious adverse events were clearly tied to the drug, and monitoring of heart rhythm, vital signs, and blood chemistry turned up nothing of concern. The reported effects are generally mild.

Most common by far: redness, pain, swelling, or itching at the injection site. Rotating sites helps.
Less often: headache, mild dizziness, nausea, or short-lived fatigue.

Even with a clean trial record, this isn't a free pass. Those trials were in supervised patients, not people self-injecting research-grade vials, and SS-31 has no safety data in pregnancy or breastfeeding. If you're pregnant, breastfeeding, managing a heart condition, or on other medications, talk to a doctor before starting. Approved or not, it's a drug.

On anti-doping, SS-31 isn't named as a specific banned substance on the WADA Prohibited List. But its single narrow approval is for a rare disease, and for the off-label uses athletes would actually pursue it has no approved therapeutic use, so it can plausibly fall under the S0 category covering substances without current regulatory approval for human use. If you compete, check GlobalDRO and assume nothing.

And for most buyers, the biggest risk isn't the molecule. It's whether the vial really contains SS-31, at the strength on the label. That comes down to where you buy it.

How to vet a source

Its non-standard amino acids make a botched synthesis the wrong molecule entirely, so demand a batch-specific third-party COA matched to your vial.

SS-31 is harder to make than a simple peptide. It uses a non-standard amino acid, Dmt, and a specific D-arginine, so a sloppy or dishonest synthesis can leave you with the wrong molecule entirely, and you can't tell from the powder. The fact that an approved pharmaceutical version now exists doesn't change what's in a gray-market vial. Where you buy matters more than almost anything else here. The one document that separates a real seller from a gamble is a certificate of analysis: a third-party lab's report on what's actually in the vial.

A real COA shows

An identity test (usually mass spectrometry) confirming the peptide is what the label says.
A purity figure from HPLC, typically 98% or higher.
A lot or batch number that matches the number printed on your vial.
A named, independent accredited lab and a recent test date.

Walk away if

There’s no COA, or it’s a generic image with no lot number.
The “certificate” comes from the seller instead of a third-party lab.
The lot number doesn’t match your vial, or there isn’t one at all.
It’s a flat image you can’t trace back to the lab that issued it.

That's the standard worth holding any seller to, ours included. Ask for the batch-specific COA before you buy, match the lot number to your vial, and don't accept a screenshot in place of a traceable report.

See the Zapify compound catalog →

Common questions about SS-31

Is SS-31 FDA-approved?

Partly, and the nuance matters. In September 2025 its drug form, elamipretide, received FDA accelerated approval under the brand name Forzinity for Barth syndrome, a rare inherited mitochondrial disease, in patients weighing at least 30 kg. That's the only approved use. It is not approved for longevity, energy, anti-aging, or general performance, which are the reasons most people buy it. For those uses it's an experimental research compound.

How is SS-31 different from BPC-157 or TB-500?

Different target and a very different evidence base. BPC-157 and TB-500 are soft-tissue repair peptides backed mostly by animal data. SS-31 targets mitochondria, the cell's energy machinery, and has been through multiple completed human trials plus one rare-disease approval, far more human exposure than the repair peptides. That doesn't make it proven for everyday use, but the research behind it is in a different league.

Did SS-31 actually work in its clinical trials?

The record is mixed. The Barth syndrome program improved muscle strength and led to approval. Larger trials in heart failure (PROGRESS-HF), mitochondrial myopathy (MMPOWER-3), and dry macular degeneration (ReCLAIM) missed their primary endpoints. So it's well studied and partly successful, not a clean win. A Phase 3 dry-AMD study, ReNEW, is still running.

Do you cycle SS-31 like a repair peptide?

Not the way it was studied. The trials used continuous daily injection, including extension studies past three years, on the logic that mitochondrial support is maintained rather than pulsed on and off. That's different from the load-and-rest cycling used for tissue-repair peptides. Whether indefinite daily use makes sense outside a trial is a question for a provider.

Why bacteriostatic water and not saline or sterile water?

Because you'll be drawing from the same vial across days. Bacteriostatic water carries a trace of benzyl alcohol that holds back bacteria between draws; plain sterile water and saline have no preservative. On a multi-dose peptide vial, the professional sources all point the same way: bacteriostatic.

References

This page is for research and educational purposes only. It is not medical advice or a recommendation to use any compound. The dose ranges shown are reported by clinics and research literature, not validated medical standards, and SS-31 is not FDA-approved. Talk to a licensed medical provider about anything you put in your body.