SS-31
Stocked in 10mg, 50mg at MontanaPep in Great Falls, Montana. Sold for laboratory research use only.
| Size | Catalog no. | Price per vial |
|---|---|---|
| 10mg | 2S10 | $30 |
| 50mg | 2S50 | $75 |
Classification
Mitochondria-targeting tetrapeptide; FDA-approved as elamipretide (Forzinity) for one rare disease
Structure and chemistry
SS-31 is the aromatic-cationic tetrapeptide H-D-Arg-Dmt-Lys-Phe-NH2, where Dmt is 2′,6′-dimethyltyrosine. The alternating cationic and aromatic side chains are the defining motif of the Szeto-Schiller (SS) peptide class. Its D-amino acid content and C-terminal amide make it resistant to peptidase degradation, and it is cell-permeable without requiring a transporter.
What the published research shows
SS-31 has an unusually deep evidence base for a compound in this catalog: extensive cell and isolated-mitochondria biophysics, wide-ranging rodent models (cardiac ischemia-reperfusion, acute kidney injury, spinal cord injury, glaucoma, age-related muscle dysfunction), and multiple human clinical trials including the randomized, double-blind, placebo-controlled TAZPOWER crossover trial in Barth syndrome that supported its FDA approval.
Mechanism of action
SS-31 concentrates in the inner mitochondrial membrane and binds reversibly to cardiolipin, the anionic phospholipid that scaffolds the respiratory complexes and anchors cytochrome c. By stabilizing cardiolipin-protein interactions it preserves cristae structure, improves electron-transport-chain coupling and ATP output, and reduces reactive oxygen species leakage. Its original antioxidant/free-radical-scavenging explanation is now considered secondary, since the related SS-20 peptide lacks a scavenging side chain yet remains active.
Development history
The SS peptides originated in opioid research, not mitochondrial research. Szeto and Schiller were developing analogues of the mu-opioid peptide [Dmt1]DALDA when structural modification reduced opioid receptor affinity roughly 2,000-fold and revealed an unexpected property: the molecule concentrated in mitochondria. Patents were filed by the Cornell Research Foundation with Szeto and Schiller as inventors, and Szeto founded Stealth Peptides (later Stealth BioTherapeutics) to develop the compound.
Current regulatory status
On September 19, 2025 the FDA granted accelerated approval to elamipretide (brand name Forzinity, Stealth BioTherapeutics) to improve muscle strength in adult and pediatric Barth syndrome patients weighing at least 30 kg — the first FDA-approved mitochondria-targeted therapeutic of any kind. The approval is narrow, covers only that ultra-rare disease (roughly 150 people in the US), and remains contingent on a confirmatory trial. Development continues in dry age-related macular degeneration and primary mitochondrial myopathy. Catalog material sold as SS-31 is a research-grade item, not the approved drug product.
Analytical testing
The exact chemical form should be verified by mass spectrometry against a certified reference standard, including confirmation of the dimethyltyrosine residue and D-amino acid configuration. HPLC purity alone does not establish sequence or stereochemistry.
Ordering from Great Falls
MontanaPep, also known as Montana Peptides, is an independently owned supplier based at 715 13th Ave S, Great Falls, Montana. Local pickup is available by arrangement, and we ship to research addresses across Montana including Billings, Missoula, Bozeman, Helena, Butte, Kalispell and Havre. Call (406) 799-0812 or email customerservice@montanapep.com.