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What it is
A synthetic tetrapeptide that concentrates in the inner mitochondrial membrane and associates with cardiolipin, a phospholipid essential to mitochondrial structure.
How it is proposed to work
Stabilising cardiolipin is proposed to preserve cristae architecture and improve electron-transport efficiency, reducing reactive oxygen species production.
Approved medical uses
None. Elamipretide (SS-31) has no approved human medical indication in the jurisdictions we track. Any use is outside an approved label.
Human research
Each entry states what the study found and, separately, what it cannot show.
- Randomised controlled trial2023n = 218
MMPOWER-3: phase-3 trial in primary mitochondrial myopathy
Finding. The trial missed both primary endpoints. Change from baseline to week 24 in distance walked on the six-minute walk test did not differ between elamipretide and placebo (p = 0.69), and neither did total fatigue on the Primary Mitochondrial Myopathy Symptom Assessment (p = 0.37). The authors report that elamipretide was well-tolerated, with most adverse events mild to moderate in severity. The paper carries a Class I evidence classification for the conclusion that elamipretide does not improve the six-minute walk test or fatigue at 24 weeks compared with placebo.
Limitation. Failure to meet the primary endpoints is the headline result, and good tolerability does not offset it — and that tolerability framing is partly the sponsor's own, since elamipretide is Stealth BioTherapeutics' compound, one co-author is a Stealth employee, and two further co-authors are paid Stealth consultants. Treatment was subcutaneous and ran 24 weeks in participants with genetically confirmed primary mitochondrial myopathy (mean age 45.6 years, 64% women, 94% White, 74% with a mitochondrial DNA alteration), so the result does not extend to longer exposure, to other routes, or to other populations, and a rare-disease population of this size remains genetically heterogeneous.
Preclinical research
Animal and laboratory work. Useful for generating hypotheses; it cannot establish that something works in people.
No preclinical studies catalogued.
Potential safety concerns
- WatchPreliminary
Injection-site reactions are the most commonly reported adverse effect in trial settings.
Known interactions and contraindication considerations
- Not well characterised outside trial settings.
This list is not exhaustive and is not a substitute for a clinician reviewing your full medication history.
Regulatory status
Status is shown per jurisdiction and is accurate only as of the date stated. Where a compound is approved, the approval is bound to a specific formulation, manufacturer and indication — shown in the detail column.
| Jurisdiction | Standing | Detail |
|---|---|---|
United States FDA | Under review as of 1 Jun 2026 | Has been through regulatory review processes for rare mitochondrial indications. Review status is not approval; verify current standing before relying on this. |
European Union EMA | Unapproved / investigational as of 1 Jun 2026 | No marketing authorisation. |
India CDSCO | Unapproved / investigational as of 1 Jun 2026 | Not approved. |
How it is being used
What the grey community actually runs, the reasoning they give, and our read on whether it follows from known biology. This is observation, not evidence, and not a recommendation.
Mitochondrial support outside a trial
What is run
Occasional grey-market use in blocks, by people extrapolating from the rare-disease programme to general fatigue or ageing.
Their mechanistic reasoning
That cardiolipin stabilisation improves mitochondrial efficiency, so anyone with fatigue or age-related decline should benefit as trial participants did.
Reported in the community’s own terms. Not our position.
Stacked with
- MOTS-c or NAD+ precursors—Bundled as general mitochondrial support.
Regimen shape
- Dose
- figure withheld
- Scale
- Milligram-scale
- Route
- Subcutaneous injection
- Frequency
- Daily in trial protocols; irregular in community use
- Timing
- No consistent convention
- Duration
- Blocks of weeks
Our read
The mechanism is the most specific and best characterised in this area — cardiolipin's role in cristae structure is real, and this is a rational drug design rather than a repurposed curiosity. The problem is what the trials actually showed: mixed results in primary mitochondrial myopathy including missed primary endpoints. Extrapolating from a programme with equivocal results in people who have a defined mitochondrial pathology, to healthy people who do not, runs in the wrong direction from the evidence.
What the community reports
The comparison is between how sure the community is and how much is actually known — evidence strength, not direction. A compound can have solid research that came out negative.
Discussed with interest because of the genuine clinical programme, but community use is rare and enthusiasm has cooled as the mixed trial results became more widely known.
Commonly reported as helping
- Improved energy, reported by a small number of users
Also reported, when it goes wrong
- Very limited availability and high cost
- Injection-site reactions
- Awareness that the trials did not clearly succeed
Why these reports can mislead
The user base is small enough that no reliable pattern exists, and the people using it are unusually invested — they have generally sought out an expensive, hard-to-obtain compound after reading the trial literature, which is a strong setup for expectation effects.
Direct quotations are not published here yet. We will only carry verbatim reports once they are sourced, dated and checked — an unattributed quote is a testimonial, and testimonials are exactly what this section exists to replace.
Watch for, in this use specifically
- Injection-site reactions are the most commonly reported effect in trials.
- The trial results are mixed, not positive. The extrapolation starts from weaker ground than the community assumes.
Active clinical trials
- NCT00000004Phase 3Completedn = 218
Cardiolipin-targeted peptide in primary mitochondrial myopathy
Primary mitochondrial myopathy · United States · updated 28 Feb 2026
What remains unknown
The questions that would change our assessment if they were answered.
- Which patient subgroups, if any, respond?
- Do mitochondrial-function biomarkers translate into outcomes patients notice?
References
Editorial change history
When we change a grade or a regulatory note, we log it here rather than editing quietly.
Scheduled review; trial table refreshed.
Spotted something wrong? Tell us — we publish corrections.