Mechanism, dosing tables, reconstitution guide, Phase 2 clinical trial data, and COA-verified vendor pricing — all in one place.
SS-31 (Elamipretide, MTP-131) is a cell-permeable, mitochondria-targeted tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH₂. It accumulates selectively at the inner mitochondrial membrane (IMM) by interacting with cardiolipin — a phospholipid unique to the IMM that is essential for organizing the electron transport chain (ETC) supercomplexes responsible for ATP synthesis.
| Property | Value |
|---|---|
| Other names | Elamipretide, MTP-131, Bendavia, SS-31 |
| Sequence | D-Arg-Dmt-Lys-Phe-NH₂ |
| Molecular weight | ~640 Da |
| Half-life | ~2 hours (SubQ); shorter IV |
| Primary target | Cardiolipin / inner mitochondrial membrane |
| Routes studied | Subcutaneous injection, IV infusion |
| Storage | Lyophilized: -20°C preferred; reconstituted: refrigerate, use within 30 days |
| Reconstitution | Sterile or bacteriostatic water |
| Clinical stage | Phase 2 completed (HFpEF, AKI) |
SS-31 dosing in research is considerably lower than most peptides by weight, reflecting its potency at the mitochondrial level. Clinical trials used IV infusion; research community protocols use SubQ injection.
| Context | Dose | Frequency | Duration |
|---|---|---|---|
| Clinical (HFpEF trials) | 0.05–0.25 mg/kg IV | Single or repeated infusion | Trial-specific |
| Clinical (AKI prevention) | 0.05 mg/kg IV | Single pre-operative dose | One-time |
| Preclinical aged animals | 3 mg/kg/day SubQ | Daily | 4–8 weeks |
| Research community (SubQ) | 5–10 mg/day | Daily or 5 on / 2 off | 4–12 weeks |
Research community subcutaneous dosing (5–10mg/day) is extrapolated from preclinical data and is not derived from controlled human trials. The clinical IV doses were significantly lower by mg/kg. This is an area where the gap between animal model data and human research protocols is large.
SS-31 typically comes as a lyophilized powder in 50mg vials. Reconstitute with 2.5mL bacteriostatic water for a concentration of 20mg/mL. At a 10mg research dose, that's 0.5mL (50 units on a U100 insulin syringe). Inject subcutaneously — abdomen, thigh, or shoulder are common sites.
| Vial Size | BAC Water | Concentration | Volume per 5mg | Volume per 10mg |
|---|---|---|---|---|
| 50mg | 2.5mL | 20mg/mL | 0.25mL (25 units) | 0.50mL (50 units) |
| 50mg | 5mL | 10mg/mL | 0.50mL (50 units) | 1.0mL (100 units) |
The most compelling preclinical data for longevity researchers is Siegel et al. (2013), which showed that 8 weeks of daily SS-31 injections in 24-month-old rats (equivalent to ~70-year-old humans) restored skeletal muscle mitochondrial function to levels comparable to young animals. Specifically: ATP production rates, mitochondrial membrane potential, and exercise capacity all improved significantly. This single paper underpins much of the research community interest in SS-31 for aging applications.
Stealth BioTherapeutics ran two major Phase 2 trials. PROGRESS-HF tested IV SS-31 in heart failure with preserved ejection fraction — the trial missed its primary endpoint (6-minute walk distance) but showed signals in secondary endpoints including exercise capacity and quality of life measures. EMBRACE-HF tested it for heart failure and was terminated early when the company ran out of funding, not due to safety concerns.
Multiple Phase 1/2 trials tested SS-31 for acute kidney injury prevention in cardiac surgery patients. The HARP trial and related work showed reductions in AKI biomarkers with IV SS-31, with a favorable safety profile. This is the application with the most consistent positive human signal.
In high-fat diet rodent models, SS-31 improved insulin sensitivity, reduced hepatic fat accumulation, and increased skeletal muscle fat oxidation — effects attributed to improved mitochondrial efficiency rather than direct metabolic signaling.
SS-31's relatively long half-life (~2 hours) compared to other peptides means once-daily dosing is sufficient for sustained mitochondrial exposure. Most preclinical protocols ran daily for 4–8 weeks.
SS-31 stabilizes ETC structure and reduces ROS; MOTS-c activates AMPK and shifts metabolic substrate utilization. These act on different aspects of mitochondrial biology and are commonly paired in longevity research protocols for potentially additive effects.
SS-31 has a notably clean safety profile based on clinical trial data — a meaningful distinction from compounds where human safety data is limited to case reports.
The Phase 1 SAD/MAD (single and multiple ascending dose) studies established tolerability up to 0.25 mg/kg IV with no dose-limiting toxicities. This is the strongest safety basis available for any research peptide in this class.
COA-verified vendor pricing with promo codes. Two vendors currently carry SS-31.
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