SS-31 is elamipretide, a peptide that concentrates in the inner mitochondrial membrane where it interacts with cardiolipin, a lipid essential to how mitochondria produce energy. It is being developed as a prescription medicine for rare genetic mitochondrial disorders.

In its lead indication, the controlled answer so far is no. The trial in primary mitochondrial myopathy states plainly that it did not meet its primary endpoints and that treatment did not improve the outcomes measured. There is a more encouraging signal in Barth syndrome, but it comes from an open-label extension, which is a weaker design.

Has SS-31 been tested for anti-aging or energy in healthy people?

No. Every randomised trial we located is in patients with a diagnosed condition - primary mitochondrial myopathy, Barth syndrome, or an eye disease. Nobody has run a controlled trial of SS-31 in healthy adults for the outcomes it is marketed for online.

What is the SS-31 dosage?

The trials used subcutaneous elamipretide under clinical supervision in patients with diagnosed mitochondrial disease. Applying a dose from a trial in a rare genetic disorder to a healthy adult buying a research chemical is not a translation we are willing to make, and the trial that used it did not show benefit on its primary outcomes anyway.

It is not approved for the uses it is sold for online, and it is supplied through research-chemical channels where the contents of the vial are not verified by anyone.

Research peptides

SS-31 (Elamipretide): The Phase 3 Trial Missed Its Endpoints

SS-31 is a real drug in real trials for rare mitochondrial disease, not aging. Its largest controlled trial missed its primary endpoints. Vendors omit that.

Written bySebastian Hunter, Founder and Editor

Published August 23, 2026

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Plain English

SS-31, or elamipretide, is a mitochondria-targeted peptide being developed as a medicine for rare genetic mitochondrial diseases. It has a substantial trial programme, which is unusual here. Its largest controlled trial did not meet its primary endpoints. It is sold online as a longevity peptide to people who do not have those diseases.

Genuinely in clinical development - 16 randomised trials on PubMed.
The lead Phase 3 in mitochondrial myopathy did not improve its primary outcomes.
No trial has tested it in healthy adults for aging or energy.

SS-31 is not one of the compounds we cover where the research is thin and the marketing is thick. The research is substantial. Pharmaceutical companies have run randomised, controlled, multicentre trials of this molecule in real patients.

That is exactly why the result deserves a page of its own — because the headline finding is not the one the vendors quote.

What it is

SS-31 is elamipretide. It concentrates in the inner mitochondrial membrane and interacts with cardiolipin, a lipid the machinery of energy production depends on. The proposition is that a peptide which stabilises that machinery could help in diseases where it is failing.

That is a serious idea, and it has been tested seriously.

Where it has been tested

Randomised SS-31 trials cited here, by population

Primary mitochondrial myopathyincluding the lead Phase 3
3
Barth syndromeultra-rare genetic disorder
1
Eye disease, topicala different formulation entirely
1
Healthy adults, aging or energythe marketed use
0

Every controlled trial we located is in patients with a diagnosed condition. The people buying SS-31 as a longevity or energy peptide are the one group nobody has studied.

The programme in primary mitochondrial myopathy ran through dose-escalation Karaa 2018 - Karaa A, Haas R, Goldstein A et al. Randomized dose-escalation trial of elamipretide in adults with primary mitochondrial myopathy. Neurology. 2018;90(14):e1212-e1221. (opens PubMed in a new tab), a randomised crossover trial Karaa 2020 - Karaa A, Haas R, Goldstein A et al. A randomized crossover trial of elamipretide in adults with primary mitochondrial myopathy. J Cachexia Sarcopenia Muscle. 2020;11(4):909-918. (opens PubMed in a new tab), and then the large controlled study Karaa 2023 - Karaa A, Bertini E, Carelli V et al. Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial. Neurology. 2023;101(3):e238-e252. (opens PubMed in a new tab). There is separate work in Barth syndrome Thompson 2024 - Thompson WR, Manuel R, Abbruscato A et al. Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER. Genet Med. 2024;26(7):101138. (opens PubMed in a new tab) and a topical ophthalmic formulation for an eye condition Karanjia 2024 - Karanjia R, Sadun AA. Elamipretide Topical Ophthalmic Solution for the Treatment of Subjects with Leber Hereditary Optic Neuropathy: A Randomized Trial. Ophthalmology. 2024;131(4):422-433. (opens PubMed in a new tab).

The result

The trial in primary mitochondrial myopathy reports that it did not meet its primary endpoints, assessing the six-minute walk test and total fatigue score, and states directly that subcutaneous elamipretide “did not improve outcomes” on those measures in those patients Karaa 2023 - Karaa A, Bertini E, Carelli V et al. Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial. Neurology. 2023;101(3):e238-e252. (opens PubMed in a new tab).

The more encouraging result, and its design

In Barth syndrome — an ultra-rare X-linked disorder — elamipretide was associated with sustained tolerability and with improvements in functional assessments and cardiac function Thompson 2024 - Thompson WR, Manuel R, Abbruscato A et al. Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER. Genet Med. 2024;26(7):101138. (opens PubMed in a new tab).

Read that alongside how it was produced. Those improvements come from an open-label extension: everyone knew who was receiving the drug, and there was no concurrent placebo group. That is a weaker design than the trial that failed, and in a condition affecting a tiny number of people worldwide.

It is a real signal worth following. It is not evidence that a healthy adult will feel more energetic.

Dose, and why we are not translating one

The trials administered subcutaneous elamipretide to patients with diagnosed mitochondrial disease, under clinical supervision, with monitoring.

We report doses where a study establishes one for the use in question. Here the studied doses belong to rare genetic disorders, and the largest of those trials did not show benefit on its primary outcomes. Carrying a number from that setting to a healthy adult buying a vial online would be inventing a translation the evidence does not support.

Status

US legal status - Research use only · not for human use

Sold for laboratory research use only. Not approved by the FDA for human use, and cannot be lawfully marketed as a supplement or a medicine. Products sold this way are not made to pharmaceutical quality standards, and their contents are not verified by anyone.

SS-31 is sold as a research chemical. That is the legal basis on which a vendor can sell it at all, and it means the contents of the vial are not verified by anyone — an odd position for a molecule that also exists as a carefully manufactured investigational medicine.

References

Bibliographic detail is fetched from PubMed, not written by us - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than our judgement.