SS-31
Also known as Elamipretide, MTP-131, Bendavia, Forzinity, D-Arg-Dmt-Lys-Phe-NH2
SS-31 (elamipretide) is a synthetic mitochondria-targeted tetrapeptide that binds cardiolipin in the inner mitochondrial membrane. It is studied in mitochondrial disease and aging, and in the US it holds accelerated approval for Barth syndrome.
Approved drug substance
Size
2 options- Catalog no.
- 2S10
- Specification
- 10mg*10vials
- Per kit
- 10 vials
For laboratory research use only. Not for human or animal consumption. Buyers must be 21 or older.
Overview
SS-31 is one of the Szeto-Schiller peptides, a series of small aromatic-cationic peptides developed by Hazel Szeto and Peter Schiller that cross cell membranes and concentrate in mitochondria. Its sequence is D-Arg-dimethyltyrosine-Lys-Phe-amide. As elamipretide, developed by Stealth BioTherapeutics, it has been tested in primary mitochondrial myopathy, Barth syndrome, heart failure, and dry age-related macular degeneration. In September 2025 the FDA granted accelerated approval to elamipretide (Forzinity) for Barth syndrome, based on knee extensor muscle strength, with a confirmatory trial required. Preclinical work has examined it in aged skeletal muscle and in heart and kidney injury models.
Class: Mitochondria-targeted, cardiolipin-binding tetrapeptide
Mechanism of action
How the compound acts, as described in the literature.
Alternating aromatic and basic residues give it a net positive charge that lets it cross membranes and accumulate at the inner mitochondrial membrane.
Binds cardiolipin, a phospholipid of the inner membrane that supports cristae structure and the organization of electron transport chain complexes.
In preclinical models, cardiolipin binding has been associated with preserved cristae, improved electron transport and ATP production, and lower mitochondrial reactive oxygen species.
Reported to inhibit the peroxidase activity of cytochrome c bound to cardiolipin, a step linked to cardiolipin oxidation and the start of apoptosis.
Published research
Selected studies, each linked to its PubMed record. Summaries describe what the studies reported.
2013
Rodent study
PMID 23692570Mitochondrial-targeted peptide rapidly improves mitochondrial energetics and skeletal muscle performance in aged mice.
Siegel MP, et al. · Aging Cell
In aged mice, a single SS-31 exposure restored in vivo muscle mitochondrial ATP production and coupling toward young levels within an hour. Eight days of exposure increased endurance capacity. Young muscle was unaffected.
2021
Phase 2/3 RCT
PMID 33077895A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome, a genetic disorder of mitochondrial cardiolipin metabolism.
Reid Thompson W, et al. · Genet Med
In 12 people with Barth syndrome, the placebo-controlled crossover phase did not meet its primary endpoints. In the open-label extension, 6-minute walk distance and knee extensor strength had improved at 36 weeks.
2023
Phase 3 RCT
PMID 37268435Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial.
Karaa A, et al. · Neurology
MMPOWER-3 randomized 218 adults with primary mitochondrial myopathy to elamipretide or placebo for 24 weeks. It did not meet its primary endpoints (6-minute walk test and fatigue score). Elamipretide was generally well tolerated.
Evidence & safety
What the research does not show, and the adverse events and regulatory status it reports.
US approval, as Forzinity, is an accelerated approval for Barth syndrome only, based on knee extensor strength, and continued approval depends on a confirmatory trial. The Barth trial enrolled 12 people and missed its primary endpoints in the placebo-controlled phase, and the phase 3 MMPOWER-3 trial in primary mitochondrial myopathy also missed its primary endpoints. Injection-site reactions were the most common adverse reactions, and the label warns of serious hypersensitivity reactions.
Specifications
All sizes, exactly as catalogued.
| Catalog no. | Product | Specification | Vials per kit |
|---|---|---|---|
| 2S10 | SS-31 | 10mg*10vials | 10 |
| 2S50 | SS-31 | 50mg*10vials | 10 |
For laboratory research use only. Not for human or animal consumption. Not intended to diagnose, treat, cure or prevent any disease. Research summaries are provided for educational purposes and do not describe this product’s use.