SS-31
ElamipretideMTP-131BendaviaEvidence
Clinical
Half-life
2.5 h
Typical vial
10 mg
Route
Subcut
What it is
A mitochondria-targeting peptide that reached phase 3 and missed its primary endpoints. The most rigorously tested compound on this site, and a cautionary tale about mechanism.
SS-31 is a four-amino-acid peptide that concentrates in the inner mitochondrial membrane and binds cardiolipin, a lipid found almost nowhere else in the cell. Cardiolipin holds the folded structure that the energy-producing machinery sits on, and it degrades with age and in mitochondrial disease. Stabilising it is a genuinely elegant idea, and in cells and animals it works: mitochondria produce more ATP and leak fewer reactive oxygen species.
It is on this site for a reason that has nothing to do with the usual gray-market story. SS-31, as elamipretide, went through a full pharmaceutical development programme: phase 1, phase 2, and a randomised phase 3 trial in primary mitochondrial myopathy. That makes it the most rigorously tested compound in the longevity category by a wide margin.
The phase 3 trial missed both of its primary endpoints. Over 24 weeks in 218 patients it did not significantly improve the six-minute walk distance or the fatigue score against placebo, despite a phase 2 result that had looked promising. That outcome is the most useful information on this page. A compelling mechanism, good animal data and an encouraging early trial are exactly what every compound in this category has. Here we get to see what happened when one of them was finally tested properly.
How it works
SS-31 carries an alternating aromatic-cationic structure that drives it into the inner mitochondrial membrane independently of the membrane potential. That is unusual. Most mitochondria-targeting molecules need a healthy membrane potential to accumulate, so they work least well in the damaged mitochondria you would actually want to treat.
There it binds cardiolipin, the lipid that organises the folded cristae where the electron transport chain sits. Cardiolipin becomes damaged and depleted with age and in mitochondrial disease, cristae flatten, and energy production falls. SS-31 stabilises the interaction between cardiolipin and cytochrome c, which in laboratory models restores cristae structure and improves ATP output.
A consequence of that binding is reduced electron leak, and so fewer reactive oxygen species. This is often described as antioxidant activity, but it is not a scavenging effect. It reduces production at source instead of mopping up afterwards.
The gap between all of this and the phase 3 result is the thing worth sitting with. The mechanism is real and demonstrated. It did not translate into a measurable functional benefit in the patients it was tested in.
What it is studied for
Each entry states the evidence behind it. We do not rank indications by effectiveness — for most compounds here, that would be a claim nobody can support.
Primary mitochondrial myopathy
Clinical trialThe indication it was actually developed for.
EvidenceA randomised phase 3 trial in 218 patients missed both primary endpoints over 24 weeks. This is the highest-quality evidence about the compound and it is a negative result.
Barth syndrome
Clinical trialA rare genetic disorder of cardiolipin metabolism.
EvidenceA small crossover trial found no significant benefit in its primary endpoints, though an open-label extension reported improvements. A tiny population, and not a settled result.
General mitochondrial ageing
Community practiceWhy it is bought as a research chemical.
EvidenceNo human trial has studied SS-31 in healthy people for ageing or performance. The rationale is mechanistic and preclinical.
Regulatory status
Last reviewed 16 Aug 2026. Positions in this category change frequently, so we date the line.
Not approved for any indication. Elamipretide has been through phase 3 clinical trials that did not meet their primary endpoints. Development has continued in narrower rare-disease indications. Material sold as SS-31 is a research chemical, not the clinical product.
Identity and clearance
What the molecule is, and how long a dose stays measurable.
Molecule
- Class
- Aromatic-cationic mitochondria-targeting tetrapeptide
- Molecular weight
- 639.8 Da
- Length
- 4 amino acids
Sequence
D-Arg-Dmt-Lys-Phe-NH2
The alternating charged and aromatic residues are what let it cross into the inner membrane without depending on membrane potential.
Pharmacokinetics
Clinical trialShort plasma half-life, but it accumulates in mitochondria at concentrations far above plasma. Plasma levels are a poor guide to what is happening where the drug acts.
Dose protocols reported in sources
Displayed for reference only. Every row says where it came from, and a trial protocol and a community convention are not the same kind of information. None of this is fed into the calculator, and none of it is a recommendation.
A week-by-week progression is also reported for SS-31. See it against a 50 mg vial, where the syringe units can be worked out.
| Goal | Dose | Frequency | Route | Units, 50 mg vial | Source | Start this protocol |
|---|---|---|---|---|---|---|
| Phase 3 protocol | 40 mg | Once daily | Subcutaneous40 mg daily, which is very large by peptide standards and sits a long way above the figures that circulate in community sources. This was the dose that did not meet its endpoints. | 80 u | Clinical trial | Start this |
| Commonly described community protocol | 5 mg – 20 mg | Once daily | SubcutaneousCommunity sources describe doses well below the trial dose. There is no evidence behind either the smaller figure or the assumption that a lower dose achieves anything the trial dose did not. | 10–40 u | Community practice | Start this |
The doses above in syringe units, for the vial you have:
Start this copies a row into a protocol of your own, which you can then edit. Where a source gave a dose range or an ambiguous frequency, those fields arrive empty — we will not pick a number on your behalf.
CheckRows marked community practice describe what people commonly do, drawn from public discussion. They are not derived from any trial and are not evidence that a dose is safe or effective.
Work out what to draw
Pre-filled with a 50 mg vial as a worked example. These are not recommended values — change them to match the vial in front of you.
Draw to 40 units on a 1 mL U-100 syringe. That is 0.4 mL, containing 10 mg of SS-31.
40 units sits exactly on a printed line.
BioAlmanac performs arithmetic on values you enter. It does not recommend doses, schedules or compounds, and nothing here is medical advice. Confirm every calculation against your vial and syringe before drawing, and speak with a licensed healthcare provider.
Open this calculation in the full calculator
Units, concentration, bacteriostatic water — the glossary defines the vocabulary, and a unit is not a fixed volume.
Safety
Reported effects, the situations that need care, and the ones that mean stop.
Reported effects
- Injection site reactionsClinical trial
Very common — the majority of participants in phase 3
Redness, itching and pain at the site. Substantially more frequent than with most subcutaneous peptides, and the most common adverse event in the trial.
- Injection site induration and nodulesClinical trial
Common in trials
Firm lumps that can persist. Daily dosing into a limited number of sites makes this worse.
- HeadacheClinical trial
Reported in trials
- Diarrhoea and nauseaClinical trial
Reported in trials
When to stop
- An injection site reaction that spreads, becomes hot, or produces pus. That is infection, not the expected irritation.
- Injection site nodules that persist between doses, leaving nowhere unaffected to inject.
- Any allergic response: rash, hives, facial swelling or difficulty breathing. Seek urgent care.
- Persistent headache or gastrointestinal upset that does not settle.
Interactions and situations that need care
- Pregnancy and breastfeedingAvoid
No reproductive or developmental safety data, and no benefit established in anyone to weigh against that.
- Expecting the phase 3 result to be wrongUse caution
The best-designed study of this compound found no significant functional benefit against placebo. Buying it anyway is a decision to weigh a mechanism above a randomised trial, which is worth making deliberately rather than by not noticing.
- Known cardiolipin-related genetic disorder, self-treatedUse caution
Barth syndrome and related disorders are exactly the populations elamipretide was studied in, under specialist supervision with cardiac monitoring. Self-treating a serious genetic condition with a research chemical instead of enrolling in that care is a worse option than it appears.
What to expect
What the sources describe over time, and how confident anyone can be about it.
- The phase 3 trial missed both primary endpoints. If you take one thing from this page, that is it.
- The mechanism is real, well characterised and demonstrated in cells and animals. That turned out not to be enough, which is the general lesson worth carrying to every other compound in this category.
- The trial dose was 40 mg daily. Community protocols describe a fraction of that, with no evidence behind either the number or the idea that less would work better.
- Injection site reactions affected most participants in the trial. Expect them.
- No human trial has studied it in healthy people for ageing, energy or performance.
Storage and combinations
How to keep it, and what it does and does not go with.
Storage and handling
- Freeze-dried powder
- Refrigerated at 2–8 °C, protected from light.
- After mixing
- Refrigerated at 2–8 °C. Do not freeze once mixed.
- Long-term, frozen
- Unopened powder is stable at −20 °C or colder.
Checking your vial
Research chemicals carry no manufacturing standard, so what the vial looks like is often the only quality signal available before you use it.
White cake, clear solution
Standard for a short peptide.
Collapsed cake or cloudy solution
Heat damage or degradation. Do not use it.
Vocabulary on this page
- Subcutaneous
- Into the layer of fat beneath the skin rather than into muscle. The route almost every peptide on this site uses.
- Research chemical
- A legal label, not a quality grade. It describes what a seller is permitted to sell you, and says nothing about what is in the vial.
- Evidence level
- The category of human evidence behind a compound, from preclinical through to approved. Stated on every profile here as a category, not an adjective.
- Injection site
- Where on the body an injection is given. Rotating between sites is standard practice for anything given repeatedly.
- Peptide
- A short chain of amino acids: the same building blocks as a protein, in a chain short enough to behave differently.
- Protocol
- One compound, with a dose, a frequency and a length: the plan, as opposed to what was actually taken.
Questions
- If it failed phase 3, why is it still sold?
- Failing a trial endpoint is not the same as being inert, and the mechanism remains scientifically interesting. Development has continued in narrower rare-disease indications. But 'still being investigated' and 'shown to work' are different states, and the best evidence available says it did not produce a measurable functional benefit in the patients tested.
- Is SS-31 the same as elamipretide?
- Yes. SS-31 is the research designation and elamipretide is the drug name. The clinical trial product was manufactured to pharmaceutical standards; a research chemical shares the sequence and nothing else.
- How does it differ from an antioxidant supplement?
- It is not a scavenger. Rather than neutralising reactive oxygen species after they form, it stabilises the cardiolipin structure so fewer are produced in the first place. Whether that distinction translates into a benefit in people is precisely what the phase 3 trial failed to show.
References
Everything on this page that came from a source, with the source.
Elamipretide in patients with primary mitochondrial myopathy: the MMPOWER-3 randomised clinical trial
Neurology, 2022 · Randomised, double-blind, placebo-controlled phase 3 trial
Adults with genetically confirmed primary mitochondrial myopathy · n = 218 · 40 mg subcutaneous, once daily · 24 weeks
Did not meet either primary endpoint: no significant improvement in six-minute walk distance or in total fatigue score against placebo. Injection site reactions were the most common adverse event, affecting the majority of treated participants.
Elamipretide in Barth syndrome: the TAZPOWER crossover trial
Genetics in Medicine, 2021 · Randomised, double-blind, placebo-controlled crossover trial
Adolescents and adults with Barth syndrome · n = 12 · 40 mg subcutaneous, once daily · 12 weeks per period
No significant difference from placebo in the primary endpoints during the blinded phase. An open-label extension reported improvements, which an uncontrolled extension cannot separate from natural variation or expectation.
Commonly reported community protocols
BioAlmanac editorial summary of public community sources, 2026 · Not a study
Records dose patterns described in public discussion, which are consistently far below the trial dose. Carries no evidential weight about safety or effect.
Compiled community protocols
BioAlmanac editorial summary of a public protocol compilation, 2026 · Not a study
Records a week-by-week progression described on a vendor-adjacent protocol site, retrieved August 2026. Only the doses are taken from it. Its own syringe-unit conversions were checked against the vial sizes it states and several understate the volume by half, so nothing computed by that source is reproduced here — the units on this site are worked out from the vial in front of you. Carries no evidential weight about safety or effect.
SS-31 compared with
Also compared with GHK-Cu, Ipamorelin, CJC-1295, Tesamorelin, MK-677, GHRP-2.
Related compounds
GHK-Cu
A naturally occurring copper-binding tripeptide with a long history in topical skincare research. Injected use is not what the research studied.
Ipamorelin
A selective growth hormone secretagogue that prompts a short pulse of GH release. Widely used, and supported almost entirely by early pharmacology rather than outcome trials.
CJC-1295
A GHRH analogue that raises growth hormone by amplifying the body's own release signal. Sold in two forms whose durations differ by two orders of magnitude.
Tesamorelin
A GHRH analogue approved by the FDA for reducing excess visceral fat in HIV-associated lipodystrophy. The only compound in this category with completed phase 3 trials.
Next
What to do with SS-31
- Keep a record of itTurn a dose and a schedule into a protocol, then log what you actually take. SS-31 is filled in for you.
- See what it costsPer-milligram prices read from vendor sites and confirmed by a person, so vial sizes compare.
- Check a combinationWhat our profiles record about SS-31 alongside each other compound — including the pairs where nothing is recorded.
Keep this page honest
If something here is wrong, out of date, or missing a source, tell us and we will fix it and say that we did.
This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on BioAlmanac is medical advice. No clinician reviews these pages.
Page last updated 16 Aug 2026