SS-31 — questions, answered plainly.

SS-31 (Szeto-Schiller-31, also known as elamipretide or MTP-131) is a synthetic mitochondria-targeted tetrapeptide. It accumulates in the inner mitochondrial membrane via interaction with cardiolipin and is investigational across multiple clinical programmes.

SS-31 has a sequence (D-Arg-DMT-Lys-Phe-NH2) that gives it both cell-permeability and selective affinity for cardiolipin, a phospholipid concentrated in the inner mitochondrial membrane. This allows the peptide to localise to mitochondria without an active transport step.

No. SS-31 (elamipretide) is investigational at the time of writing. Multiple Phase II / III trials have been conducted across Barth syndrome, primary mitochondrial myopathy, dry AMD, and heart failure — primary endpoints have been mixed.

Zhao et al. 2019 (J Neuroinflammation, PMID 31747905) reported reversal of LPS-induced memory deficits in mice via mitochondrial-dysfunction reduction. Tse et al. 2020 (Exp Eye Res, PMID 32758490) reported improved retinal ganglion cell survival after optic nerve trauma in a mouse model.

The Nashine 2021 Cells review (PMID 34572131) frames SS-31 / elamipretide among therapeutic candidates targeting mitochondrial dysfunction and oxidative stress in age-related macular degeneration. The ReCLAIM-2 Phase III trial in dry AMD reported a missed primary endpoint.

Investigational. Multiple Phase II / III trials have produced mixed primary-endpoint outcomes. Most published mechanism research is preclinical; the clinical evidence base continues to consolidate.