SS-31 (also called elamipretide, MTP-131, or Bendavia) is a peptide that targets the inner membrane of mitochondria, the structures inside every cell that generate energy. It's being studied in formal clinical trials for heart failure and rare mitochondrial diseases, and it's attracted growing interest in the longevity and anti-aging research community for its proposed effects on cellular energy production and oxidative stress.
It's one of the more unusual peptides in the research space: the mechanism is unusually well-characterized, the clinical trial data is unusually strong (for a research peptide), and the dosing questions are legitimately unsettled.
What the Research Shows
The published evidence on SS-31 divides into two buckets: well-funded clinical research (heart failure and mitochondrial disease) and early-stage animal and in-vitro work (longevity, cognitive function, metabolic health). They're worth keeping separate.
Clinical trial data (human, formal):
SS-31 / elamipretide has been studied in Phase 2 trials for heart failure with preserved ejection fraction (HFpEF) and in the TAZPOWER trial for Barth syndrome (a rare mitochondrial cardiomyopathy). The Barth syndrome trial showed statistically significant improvement in exercise capacity and heart function with dosing injected just under the skin, strong enough that elamipretide (brand name Forzinity) received FDA accelerated approval for Barth syndrome in September 2025, the first FDA-approved mitochondria-targeted drug. The HFpEF trial results were mixed: some endpoints improved, others didn't. Outside Barth syndrome, elamipretide is not approved for any use, which is the honest read of the data.
Animal-study data (what's generating the longevity interest):
Animal model studies have shown SS-31 reversing age-related mitochondrial dysfunction, reducing oxidative stress markers, and improving muscle function in aged mice. A 2020 study in Aging showed improvements in mitochondrial respiration and exercise capacity in aged mice. This is the data the research community is most interested in for non-cardiac applications — but it's animal model data, not human data.
Bottom line on the evidence: The mechanism is sound and the mitochondria-targeting approach has legitimate human clinical backing. The longevity and energy applications are biologically plausible but not yet tested in humans. This is a higher-evidence-quality peptide than many in the research space, but the human data is specifically for heart conditions — not the off-label applications most researchers are exploring.
Community vs. Research Evidence: Where They Diverge
This is one of the peptides where the community is ahead of the published human research.
| What the research has studied | What the community reports studying it for |
|---|---|
| Heart failure (HFpEF, Barth syndrome) | Energy and fatigue (especially perimenopause-related) |
| Mitochondrial disease | Brain fog and cognitive sharpness |
| Exercise capacity in heart patients | Recovery after exertion |
| Age-related cardiac function (animal) | General longevity and cellular aging |
The community is extrapolating from a solid mechanistic foundation to applications that make biological sense but haven't been tested in human trials. That's not the same as having no basis; it's an informed extrapolation. It's also worth knowing that's what it is.
Expected Progress and Timeline: Community-Reported
The following reflects what researchers report in community settings. It is not clinical data, is not verified by PPL, and doesn't constitute evidence of efficacy. Individual experiences vary significantly.
Weeks 1–2:
Most people report nothing obvious in the first two weeks. Some note mild changes in sleep quality. This is consistent with a compound working at the cellular energy level: changes aren't felt the way stimulants are.
Weeks 3–6:
This is where community reports diverge the most. A segment reports noticeable changes in subjective energy, described variously as "easier to sustain effort," "less afternoon crash," or "recovery feels faster." Another segment reports nothing through this window.
8–12 weeks:
Researchers who report positive outcomes most commonly identify changes in the 8–12 week window: sustained energy, reduced perception of fatigue during exertion, and (in women managing perimenopause fatigue specifically) some reports of meaningful improvement. A subset report nothing and discontinue.
What affects it: Dosing protocol, injection site, quality of the peptide (purity matters more for this compound given the mechanism), and baseline mitochondrial health all appear to affect whether and when people notice anything.
Community Protocols Table
Community-reported protocols only. These are not clinical guidelines, not PPL recommendations, and not medical advice. Reproduced here so researchers have a realistic picture of what the research community is actually doing.
| Parameter | Range reported in community | Notes |
|---|---|---|
| Dose | 5–20 mg/week total | Most common: 10 mg/week split across 5 days (2 mg/day) |
| Single injection | 1–4 mg | More common in higher-frequency protocols |
| Frequency | Daily to 3x/week | Daily appears more common in community protocols |
| Route | Injected just under the skin | Some IM reports; under-the-skin most discussed |
| Injection site | Just under the skin, varies | Local vs. systemic debate; community leans systemic |
| Cycle length | 4–12 weeks | Some researchers run it ongoing |
| Reconstitution | Bacteriostatic water | Standard |
The injection site question: The research community has an ongoing discussion about whether injection site under the skin matters for a compound targeting mitochondria systemically. The weight of community discussion leans toward systemic effect regardless of site, consistent with SS-31's mechanism (it distributes to mitochondria throughout the body). The formal cardiac trials used injections just under the skin of the abdomen. PPL covered the injection site evidence in Dispatch No. 08.
Enter your vial, bac water amount, target dose, and syringe — and we'll tell you exactly where to draw to.
Purity and Sourcing Notes
SS-31 is one of the harder peptides to synthesize correctly, and purity matters more here than with simpler compounds. The CAS number for elamipretide is 736992-21-5; a COA should reference that specifically.
Look for ≥98% purity by HPLC. A COA showing the correct CAS and an HPLC purity result from a named third-party lab is the minimum bar. See current SS-31 prices and vendor COA status in the price tool →
What to Watch
SS-31 is not a well-understood peptide at the doses the community is using. The clinical trials used doses and administration routes determined by pharmaceutical development processes that don't map directly to the research-peptide context. The longevity and energy applications are extrapolated, not proven. If you're researching this compound, the honest read is: strong mechanistic case, solid human data for cardiac applications, and genuine uncertainty about everything else.
Research use only. Peptide Price Lab is an editorial calculator. Nothing here is medical advice. Consult a qualified clinician.