SS-31 (Elamipretide)
What it is
SS-31 (elamipretide, also referenced as MTP-131 or historically Bendavia) is a small, cell-penetrating tetrapeptide of the Szeto-Schiller (SS) peptide family. It is an aromatic-cationic mitochondria-targeting molecule that concentrates at the inner mitochondrial membrane, where it associates with the phospholipid cardiolipin.
Research context and categorization
SS-31 falls under the cellular energy and mitochondrial-function category of research compounds, sometimes grouped more broadly with metabolic and tissue-protection agents. Its defining feature in the literature is that it binds cardiolipin on the inner mitochondrial membrane, and it is studied in the context of how that interaction relates to cristae structure, electron transfer, oxidative stress, and adenosine triphosphate (ATP) production.
In preclinical and clinical research it has been investigated for a range of conditions tied to mitochondrial dysfunction, and is commonly discussed in relation to heart failure and cardiomyopathy, ischemia and reperfusion injury, kidney disease, skeletal muscle injury and atrophy, neurodegenerative disease models, and rare inherited mitochondrial disorders. Aside from its single approved indication (see Status), these uses remain investigational. They are the subject of ongoing study rather than confirmed or approved benefits, and results described in early research should not be read as established for general use.
Status
- Regulatory status: FDA-approved (September 19, 2025, under accelerated approval) as elamipretide HCl, marketed as FORZINITY by Stealth BioTherapeutics, for Barth syndrome in adult and pediatric patients weighing at least 30 kg. This is a narrow, single-indication approval, and it was the first FDA approval of any mitochondria-targeted peptide. For every other use the compound is investigational, and material sold for laboratory work is handled as a research-only compound outside that approved pathway.
- Sport status: Not specifically named as an identified substance on the current WADA Prohibited List. Its status has been discussed because it is a peptide affecting cellular metabolism, and because approval can shift how such a compound is classified, so this could be revisited. Any competing athlete should confirm the current status with their national anti-doping authority before assuming it is permitted.
Reconstitution notes (general)
SS-31 is generally supplied as a lyophilized (freeze-dried) powder that is reconstituted before laboratory use. Concentration equals the milligrams of peptide in the vial divided by the millilitres of bacteriostatic water added. For example, a 10 mg vial plus 2 mL of water gives 5 mg/mL, while the same vial plus 1 mL gives 10 mg/mL. A reconstitution calculator is available at our reconstitution and blend calculators.
Dilution and handling notes (compound-specific)
Common practice places most preparations in roughly the 2.5 mg/mL to 10 mg/mL range. A frequent approach is about 1 to 2 mL of bacteriostatic water per 10 mg vial, landing near 5 to 10 mg/mL, with smaller or larger vials diluted proportionally. The choice is driven mainly by convenient measuring volume rather than a hard solubility ceiling, since SS-31 is notably water-soluble because of its cationic character and a well-made powder generally goes into solution readily to give a clear, colorless liquid.
Direct the water slowly down the inside wall of the vial rather than onto the powder cake, then let it dissolve passively and mix by gentle swirling or inversion. Do not shake, since vigorous agitation adds foam and mechanical stress. Because the material dissolves easily, a solution that stays cloudy, will not clear, or shows floaters is usually treated as a sign of degradation or contamination rather than a normal concentrated state. The dry powder is also hygroscopic, so a vial that absorbed moisture before mixing can aggregate in a way that does not fully redissolve.
One quirk sets SS-31 apart from many peptides: it is comparatively sensitive once in solution. It contains the unusual amino acid 2',6'-dimethyltyrosine and is noted as susceptible to chemical degradation when held above refrigeration temperature in liquid form, so the reconstituted working window is treated as shorter and more temperature-sensitive than average. Keep it cold and light-protected from the moment it is mixed.
Handling and storage
Store reconstituted material refrigerated at 2 to 8 degrees Celsius and keep it out of light. Wipe the rubber stopper with an alcohol swab before each puncture, and label the vial with the mix date. Observe the general refrigerated working window of about 4 weeks, keeping in mind that SS-31 in solution is treated as less stable than many peptides, so shorter holds are common. Discard any solution that is cloudy, discolored, or contains visible particles or floaters. Lyophilized powder is more stable and is generally kept cold and light-protected, with freezer storage used for longer holds; repeated freeze-thaw cycles are avoided.
Related reading
Tools and supplies
- Reconstitution & blend calculators
- Bacteriostatic Water 30 ml
- Gansulin Metal Reusable Pen
- 3 ml Glass Cartridges (10-pack)
- Complete Starter Kit
For laboratory and research reference only. Educational content, not medical, dosing, injection, or therapeutic guidance, and not intended for human or animal use. Any research uses described are investigational and not confirmed or approved benefits. Confirm anything involving health with a licensed professional. References linked above.