SS-31 Research Peptide (Elamipretide / MTP-131 / Cardiolipin-Targeting Tetrapeptide)
Lyophilized Format • ≥99% HPLC Purity • Ships in 1–2 Business Days • U.S. Warehouses
SS-31 (Elamipretide, MTP-131, Bendavia, CAS 736992-21-5) is a synthetic tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH₂ — where Dmt is 2′,6′-dimethyltyrosine — belonging to the Szeto-Schiller (SS) family of mitochondria-targeting peptides developed by Hazel Szeto and Paul Schiller, supplied by Nextday Peptides in lyophilized format for laboratory and analytical research applications. SS-31 selectively concentrates in the inner mitochondrial membrane at 1,000–5,000× the concentration of surrounding cytoplasm through electrostatic interaction with cardiolipin — an anionic phospholipid exclusively expressed on the inner mitochondrial membrane. The first peptide to enter clinical trials as a potential treatment for mitochondrial myopathy, SS-31 has progressed through Phase 2 and Phase 3 human trials across multiple conditions. For scientific research use only.
Compound Specifications
| Compound Name | SS-31 / Elamipretide / MTP-131 / Bendavia |
| Peptide Sequence | D-Arg-Dmt-Lys-Phe-NH₂ (Dmt = 2′,6′-dimethyltyrosine) |
| Amino Acids | 4 (Tetrapeptide) — D-amino acid at position 1, C-terminal amide |
| Classification | Szeto-Schiller (SS) peptide family — inner mitochondrial membrane targeting |
| Primary Target | Cardiolipin — anionic phospholipid of inner mitochondrial membrane |
| Concentration Selectivity | 1,000–5,000× cytoplasm concentration in inner mitochondrial membrane |
| Molecular Formula | C₃₂H₄₉N₉O₅ |
| Molecular Weight | 639.8 g/mol |
| PubChem CID | 11764719 |
| CAS Number | 736992-21-5 |
| Form | Lyophilized powder |
| Appearance | White to off-white powder |
| Purity | ≥99% (HPLC verified) |
| Storage | -20°C lyophilized; 2–8°C after reconstitution |
| Synonyms | Elamipretide, MTP-131, Bendavia, D-Arg-Dmt-Lys-Phe-NH₂, SS-31 peptide |
Why Research Laboratories Select SS-31
SS-31 is unique among mitochondrial research tools — it is the only synthetic peptide that directly targets cardiolipin in the inner mitochondrial membrane with extraordinary selectivity (1,000–5,000× cytoplasm concentration), the only mitochondrial peptide with Phase 2 and Phase 3 human clinical trial data across multiple indications, and the only Szeto-Schiller peptide that has received FDA Breakthrough Therapy designation. This combination of molecular precision, mechanistic specificity, and extensive published clinical literature makes SS-31 an irreplaceable tool for mitochondrial bioenergetics, cardiolipin biology, and electron transport chain research.
- Cardiolipin-selective inner mitochondrial membrane targeting — 1,000–5,000× cytoplasmic concentration specificity
- Dmt residue (2′,6′-dimethyltyrosine) — scavenges ROS by forming unreactive tyrosine radicals that couple to di-tyrosine
- Cytochrome c peroxidase inhibition — prevents cardiolipin peroxidation that drives cytochrome c release and apoptosis
- Electron transport chain supercomplex stabilization — studied for restoration of cristae structure and oxidative phosphorylation efficiency
- Phase 2 and Phase 3 human clinical trial data — most clinically developed mitochondrial peptide in research literature
- FDA Breakthrough Therapy designation for Barth syndrome — cardiolipin biosynthesis disorder research model
- Studied in cardiac, renal, neural, skeletal muscle, and retinal research models across published preclinical literature
- Lyophilized format ensures stability and reproducibility across experimental runs
Research Background
SS-31 was developed by Hazel Szeto and Paul Schiller at Cornell University through research originally focused on opioid receptors. Szeto et al. (2014) published the cardiolipin-targeting mechanism in the Proceedings of the National Academy of Sciences. Birk et al. published findings on cardiolipin-binding and cytochrome c peroxidase inhibition in Biochimica et Biophysica Acta. Siegel et al. (2013) published Phase 2 cardiac findings. SPARCL trial Phase 3 data has been published examining SS-31 in older adults with heart failure and preserved ejection fraction. Elamipretide received FDA Breakthrough Therapy designation for Barth syndrome. Research-grade SS-31 supplied by Nextday Peptides is not equivalent to any approved pharmaceutical formulation. All information provided here is for educational and reference purposes only and does not constitute medical or clinical guidance.
Reference sources: Szeto et al. (2014) — PNAS (Cardiolipin targeting) | NIH PMC — SS-31 Kidney Disease Review
Shipping & Fulfillment
- Ships from U.S. warehouses — Florida, North Carolina, and California
- Overnight and 2-day shipping available at checkout
- Same-day processing on orders placed before 3:30 PM ET
- Discreet packaging with full tracking provided
- Bulk research orders welcome — contact us for volume pricing
Storage & Handling
- Store lyophilized peptide at -20°C away from light and moisture
- After reconstitution store at 2–8°C and use within 14 days
- Aliquot into single-use portions to avoid repeated freeze-thaw cycles
- Handle using appropriate laboratory safety protocols
- Keep containers sealed when not in use
Frequently Asked Questions
What is SS-31?
SS-31 (Elamipretide, MTP-131, CAS 736992-21-5) is a synthetic tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH₂ belonging to the Szeto-Schiller (SS) peptide family. It selectively concentrates in the inner mitochondrial membrane at 1,000–5,000× cytoplasmic concentration through cardiolipin binding. The most clinically developed mitochondrial research peptide with Phase 2 and Phase 3 human trial data. Supplied strictly for scientific, analytical, and in-vitro laboratory research use only.
What is cardiolipin and why is it important in mitochondrial research?
Cardiolipin is an anionic phospholipid exclusively expressed on the inner mitochondrial membrane where it constitutes approximately 20% of total phospholipids. It acts as both a structural component and functional cofactor for respiratory chain complexes — organizing them into “supercomplexes” for efficient oxidative phosphorylation with minimal ROS generation. Cardiolipin peroxidation and loss is associated with mitochondrial dysfunction across multiple disease research models. SS-31’s selective cardiolipin binding makes it the most precise mitochondrial membrane-targeting research tool available.
What is the role of dimethyltyrosine (Dmt) in SS-31?
The 2′,6′-dimethyltyrosine (Dmt) at position 2 of the SS-31 sequence is a modified tyrosine with two methyl groups on the aromatic ring. These methyl groups enhance membrane penetration and ROS scavenging activity. Dmt reacts with reactive oxygen species to form unreactive tyrosine radicals that subsequently couple to form stable di-tyrosine — effectively neutralizing ROS at the inner mitochondrial membrane without interfering with physiological redox signaling.
How does SS-31 differ from MOTS-c and NAD+?
SS-31, MOTS-c, and NAD+ all target mitochondrial function through entirely different mechanisms. SS-31 is a membrane-active peptide that physically binds cardiolipin to stabilize inner mitochondrial membrane architecture and electron transport chain supercomplexes. MOTS-c is a mitochondria-derived peptide that signals through AMPK and nuclear gene expression regulation. NAD+ is a coenzyme substrate for the electron transport chain and sirtuins. The three are studied as complementary mitochondrial research tools covering structural, signaling, and substrate dimensions.
What is Barth syndrome and why did SS-31 receive Breakthrough Therapy designation for it?
Barth syndrome is a rare X-linked genetic disorder caused by mutations in the tafazzin gene that result in defective cardiolipin remodeling — producing abnormal cardiolipin that cannot properly support the electron transport chain. Because SS-31 directly targets and stabilizes cardiolipin, Barth syndrome represents the most mechanistically “on-target” research model for SS-31’s cardiolipin-focused mechanism. The FDA granted Breakthrough Therapy designation for elamipretide in Barth syndrome based on this mechanistic rationale.
What purity is your SS-31?
Every batch is independently verified to ≥99% HPLC purity. A Certificate of Analysis is available for each lot.
How fast does Nextday Peptides ship?
We ship from U.S. warehouses in Florida, North Carolina, and California. Overnight and 2-day shipping options are available. Orders placed before 3:30 PM ET are processed same day.
Are bulk orders available?
Yes. We accommodate bulk research orders. Contact us directly for volume pricing and availability.
Is this product approved for medical use?
Research-grade SS-31 is not equivalent to any approved pharmaceutical formulation. Elamipretide has not received FDA approval for any indication. This product is for laboratory research use only and is not intended for diagnostic, therapeutic, or clinical applications.
What other compounds does Nextday Peptides carry?
We also carry MOTS-C, NAD+, Glutathione GSH, and SLU-PP-332. View our full research compounds catalog.
For Research Use Only — Not for human or veterinary consumption • Not FDA approved for any indication • Supplied by Nextday Peptides for controlled in-vitro laboratory research use only
