SS-31
elamipretide · Forzinity · MTP-131 · Bendavia
A peptide that acts in mitochondria, the power plants of cells. Approved in the US on a fast track as Forzinity for Barth syndrome, a rare genetic disease. Not approved in the EU.
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- Type
- Peptide
- Stage
- Approved medicine
- Safety
- Little data
- Risk of fakes
- Medium
- Checked
- Not yet
Safety. The US label covers a rare disease, Barth syndrome, and warns that benzyl alcohol in the product can harm newborns. In long follow-up, reactions at the injection site were the most common problem. Sources: US drug label, study 1.
Risk of fakes. A 2026 review lists it among peptides advertised directly to patients. We found no tests of these products. Sources: study 1.
Is it legal
| Where | Status | Checked | |
|---|---|---|---|
| PL | No approval | The European medicines database (EMA) lists no such medicine in Poland (9 October 2026). The Polish register was down, so we could not check it directly. Source | Not yet |
| EU | No approval | The European medicines database (EMA), which covers EU and national approvals, lists no such medicine (9 October 2026). Source | Not yet |
| US | Prescription only | Prescription medicine (Forzinity). Source | Not yet |
How much research exists
Scientific papers per year 2015–2025
These are search results. A count shows how much exists, not how good the studies are. 1 Nov 2026.
What studies show
- CStrength
Conflicting results. A large study in a rare muscle disease found no improvement, after small studies gave unclear results. The FDA approved it on a fast track to improve muscle strength in Barth syndrome, another rare disease. None of this concerns healthy people.
Reported side effects
What doctors, patients and companies reported to the US medicines agency (FDA), and single cases described in medical journals. A report says what happened to someone after taking the substance. It does not prove the substance caused it, and it does not say how often it happens. Reports do not change any grade.
Reports to the FDA (USA)
- Reports
- 2
- Of these, serious
- 0
| Most often reported | Reports |
|---|---|
| Reaction where the needle went in | 1 |
Serious means the person went to hospital, their life was in danger, they were left with lasting harm, or they died. One report can list several side effects. Most of these reports come from medical treatment, often of people who are ill, not from use outside medicine.
Cases described in medical journals
FDA reports come from openFDA, cases from a PubMed search. The editors have not read these cases yet. Titles stay in the original language. As of 3 Nov 2026.
Studies we have read
| Studies | Kind of study | Who was studied | People | Duration | Dose as studied | Who paid |
|---|---|---|---|---|---|---|
| Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER. | No random groups | Barth syndrome, open-label extension | 10 | 168 wk | 40 mg daily | Unknown |
| Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial. | Random groups | Adults with primary mitochondrial myopathy, phase 3 | – | 24 wk | 40 mg daily | Unknown |
| A randomized crossover trial of elamipretide in adults with primary mitochondrial myopathy. | Random groups | Adults with primary mitochondrial myopathy, crossover | 30 | 4 wk | 40 mg daily | Unknown |
| Randomized dose-escalation trial of elamipretide in adults with primary mitochondrial myopathy. | Random groups | Adults with primary mitochondrial myopathy, phase 1/2 | 36 | 1 wk | – | Unknown |
More papers we found
We found these papers automatically in PubMed. The editors have not read them yet, and they do not affect any grade. Titles stay in the original language.
Short answers
- Does SS-31 work?
- A peptide that acts in mitochondria, the power plants of cells. Approved in the US on a fast track as Forzinity for Barth syndrome, a rare genetic disease. Not approved in the EU. Strength: grade C, conflicting results. A large study in a rare muscle disease found no improvement, after small studies gave unclear results. The FDA approved it on a fast track to improve muscle strength in Barth syndrome, another rare disease. None of this concerns healthy people.
- Is SS-31 legal?
- PL: No approval. The European medicines database (EMA) lists no such medicine in Poland (9 October 2026). The Polish register was down, so we could not check it directly. EU: No approval. The European medicines database (EMA), which covers EU and national approvals, lists no such medicine (9 October 2026). US: Prescription only. Prescription medicine (Forzinity).
- Is SS-31 banned in sport?
- Not on the list, WADA 2026.
- Is SS-31 safe?
- Little data. The US label covers a rare disease, Barth syndrome, and warns that benzyl alcohol in the product can harm newborns. In long follow-up, reactions at the injection site were the most common problem.