Most peptides discussed on this site remain squarely in preclinical, research-use-only territory. SS-31 (elamipretide) is now a documented exception in one very specific way: on September 19, 2025, the FDA granted accelerated approval to an elamipretide-based drug for a rare genetic disease. This is worth covering precisely because it's easy to overstate — so here is exactly what happened, and what it does and doesn't mean.
The FDA granted accelerated approval to elamipretide HCl, marketed as FORZINITY by Stealth BioTherapeutics, for the treatment of Barth syndrome in adult and pediatric patients weighing at least 30 kg. Barth syndrome is an ultra-rare, X-linked genetic mitochondrial disease that primarily affects males and can cause cardiac and skeletal muscle complications. According to the Barth Syndrome Foundation and multiple clinical-news outlets covering the approval, FORZINITY is the first FDA-approved therapy for Barth syndrome, and the first approved drug for a primary mitochondrial disease.
The accelerated approval was supported by efficacy and safety data from the TAZPOWER clinical trial, in which participants showed improvement in knee extensor muscle strength — the strength of the muscle used to straighten the leg at the knee. The FDA considered that improvement reasonably likely to predict meaningful clinical benefits, such as an improved ability to stand or walk farther, which is the standard the agency applies for an accelerated-approval pathway (as opposed to a full approval based on a confirmed clinical-outcome endpoint). The approved drug is administered by once-daily subcutaneous injection.
This is the part a research-use audience should read carefully. The approval applies narrowly:
None of this changes the status of SS-31/elamipretide as it's sold for laboratory research: research-grade material remains not an approved drug for any use, is not the same regulated product as FORZINITY, and is supplied strictly for in-vitro and analytical laboratory work. What the approval does establish is that the underlying peptide's cardiolipin-stabilizing mechanism — the same mechanism described in the broader SS-31 preclinical literature — has now cleared FDA review for one specific, narrow clinical use, which is a meaningful data point for the mechanism generally, even though it says nothing about any other application.
Universe Peptide supplies SS-31 (elamipretide) for in-vitro laboratory research, with a third-party Certificate of Analysis (COA) available for each lot. For the mechanism background, see our SS-31 research guide.