## What SS-31 is
SS-31 is a synthetic cell-permeable tetrapeptide (D-Arg-Dmt-Lys-Phe-NH2) engineered to concentrate more than a thousand-fold inside the inner mitochondrial membrane. It has molecular formula C32H49N9O5 and mass 639.76 Da. Common synonyms in the literature include Elamipretide, Bendavia, MTP-131, and FORZINITY. SS-31's defining feature is a rationally designed alternating aromatic–cationic motif — a 2′,6′-dimethyltyrosine residue paired with D-arginine — that exploits the negative membrane potential of energized mitochondria (Δψₘ ≈ −180 mV) to selectively accumulate at the cristae, where it binds reversibly to cardiolipin, a phospholipid unique to mitochondrial membranes.
## What it's studied for
Research into SS-31 is clinical-investigational, with several completed and ongoing human trials. It became the first mitochondria-targeted therapeutic to receive FDA approval when Bendavia/FORZINITY was cleared in 2025 for Barth syndrome, a rare paediatric cardiomyopathy driven by cardiolipin dysfunction. Beyond that indication, published work referencing SS-31 spans Barth syndrome (FDA approved): Clinical trials demonstrated improved energy production, protein complex assembly, and exercise tolerance in Barth syndrome patients. Participants showed functional improvements such as walking 1 mile without breaks. FDA approval was granted based on these meaningful clinical benefits in this rare mitochondrial disorder, Primary mitochondrial myopathy trials: Phase 1/2 IV dose-escalation trial (Class I evidence) showed dose-dependent 6-minute walk test improvement (+51.2 meters at highest dose vs. +3.0 meters placebo, p=0.0297). Phase 3 MMPOWER-3 trial (NCT03323749) evaluated subcutaneous dosing with mixed results on primary endpoints, and Heart failure research: Studies in heart failure models showed improved stroke volume, ejection fraction, cardiac output, and reduced left ventricular end-diastolic pressure. Biomarkers including natriuretic peptides were reduced. Normalized bioenergetics observed in failing cardiac tissue. Proposed mechanisms cited across the primary literature include Cardiolipin interaction: binds reversibly to cardiolipin, stabilizing content and preventing peroxidation/oxidation, Cristae protection: maintains cristae structure and prevents destabilization during apoptosis, and mPTP regulation: inhibits mitochondrial permeability transition pore opening, promotes electron transfer while reducing electron leakage. A defining property, replicated across multiple in-vitro and animal models, is selectivity: SS-31 restores function in stressed, aged, or diseased mitochondria while leaving healthy mitochondria unchanged — a pharmacological profile rarely seen in bioenergetic research tools. None of this material describes therapeutic outcomes for buyers, and BioInfinity does not sell, market, or provide dosing guidance for SS-31 outside laboratory research.
## Laboratory handling — storage and reconstitution
Lyophilized SS-31 arrives as a fluffy off-white solid inside a sealed sterile vial. Because it ships as a lyophilized peptide (639.76 Da), the powder is best stored between 2–8 °C prior to reconstitution and returned to −20 °C in aliquots for long-term storage post-reconstitution. Reconstitution is typically performed with bacteriostatic water (0.9 % benzyl alcohol preserved) rather than sterile water because the preservative extends solution stability once the vial has been punctured. SS-31 is highly water-soluble owing to its net +3 charge at physiological pH, so gentle swirling — not vortexing — is sufficient to fully dissolve the powder. Warming the reconstituted solution to room temperature before drawing helps redissolve any peptide that has settled against the vial wall. Avoid repeated freeze–thaw cycles: like other short peptides, SS-31 is best protected by single-use aliquots to eliminate freeze–thaw stress between experiments.
## How this batch is verified
Every batch of SS-31 ships with a batch-specific Certificate of Analysis produced by an ISO-accredited third-party analytical laboratory. Reversed-phase HPLC confirms the assay against the expected 639.76 Da mass (C32H49N9O5); mass spectrometry validates the exact monoisotopic mass and confirms the D-arginine and dimethyltyrosine incorporation; endotoxin (LAL) testing confirms bacterial-contamination limits appropriate for laboratory research; and residual-solvent panels confirm the manufacturing pipeline. The lot number on the outer label matches the COA on the public [/coa-library](/coa-library) page — every purity claim is independently verifiable before you open the vial.
## Related research
For the full mechanistic profile, published references, cardiolipin-binding structural detail, and constraint notes on SS-31, see the [SS-31 (Elamipretide) research page](/research/ss-31). For a deeper mechanism-focused review covering the tetrapeptide's cardioprotection, neuromuscular, and age-related disorder literature, see the long-form review at [/peptide-research/ss-31-elamipretide](/peptide-research/ss-31-elamipretide). Related mitochondrial peptides carried by BioInfinity include [MOTS-c](/product/mots-c), studied for exercise-mimetic signalling and metabolic health. All references cited on the research pages are peer-reviewed primary literature.
**Research use only.** SS-31 (Elamipretide) is sold strictly for in-vitro and animal research. It is not a drug, food, supplement, or cosmetic and is not intended for human or veterinary consumption. No statements on this page describe or imply any therapeutic effect in humans.
Researchers should refer to peer-reviewed publications for primary sources on this compound. SS-31 (Elamipretide) is sold strictly for laboratory research use and is not intended for human or veterinary use.