SS-31 stands for Szeto-Schiller Peptide 31, named after its inventors Hazel Szeto and Peter Schiller. Its chemical name is D-Arg-2′6′-Dmt-Lys-Phe-NH₂, also known commercially as Elamipretide (MTP-131).
It is a synthetic tetrapeptide (4 amino acids) that selectively concentrates in the inner mitochondrial membrane where it binds cardiolipin — a phospholipid critical for electron transport chain function. It is classified as a mitochondria-targeted antioxidant and cardioprotective peptide.
SS-31's defining mechanism is its ability to bind cardiolipin — a phospholipid unique to the inner mitochondrial membrane that is essential for organizing the electron transport chain (ETC) supercomplexes. With age and disease, cardiolipin becomes oxidized and fragmented, causing ETC inefficiency, increased ROS production, and mitochondrial collapse. SS-31 intercepts this process directly at the source.
A landmark 2021 study in Nature Aging showed that SS-31 in aged mice reversed multiple hallmarks of cardiac aging in weeks — not months — restoring mitochondrial cristae architecture, reducing oxidative stress, and improving cardiac output. This is one of the most dramatic aging reversal results seen with any single compound in animal models.
SS-31 also improves ATP production efficiency, reduces mitochondrial reactive oxygen species (ROS) without scavenging them, and preserves cytochrome c in the ETC rather than allowing its release as an apoptosis trigger.
| Dose | Units to Draw | Context |
|---|---|---|
| 1 mg/kg (clinical trials) | — | IV / CLINICAL |
| 5 mg (0.05–0.1 mg/kg) | ~1.5 u | LOW / INTRO |
| 10 mg | ~3 u | COMMON |
| 20–30 mg | 6–9 u | STANDARD |
| 50 mg | 15 u | HIGH |
SS-31 primarily acts on cardiac, mitochondrial, and renal systems. Monitor the following before starting, at 6 weeks, and at cycle end.
| Biomarker | Lab Test | Clinical Range | Optimal Range |
|---|---|---|---|
| Lactate (resting) | Serum Lactate | CLINICAL0.5–2.2 mmol/L | OPTIMAL0.5–1.0 mmol/L |
| CoQ10 (Ubiquinol) | Plasma CoQ10 | CLINICAL0.4–1.9 µg/mL | OPTIMAL1.5–3.5 µg/mL |
| GDF-15 Mitochondrial stress signal | Serum GDF-15 | CLINICAL<1200 pg/mL | OPTIMAL<400 pg/mL |
| 8-OHdG Oxidative DNA damage | Urine 8-OHdG | CLINICAL<15 ng/mg creatinine | OPTIMAL<5 ng/mg creatinine |
| Biomarker | Lab Test | Clinical Range | Optimal Range |
|---|---|---|---|
| NT-proBNP Heart stress marker | Serum NT-proBNP | CLINICAL<125 pg/mL (<75 yrs) | OPTIMAL<50 pg/mL |
| Troponin I / T | High-sensitivity Troponin | CLINICAL<0.04 ng/mL (standard) | OPTIMALUndetectable / baseline stable |
| hsCRP | High-sensitivity CRP | CLINICAL<3.0 mg/L | OPTIMAL<0.5 mg/L |
| Biomarker | Lab Test | Clinical Range | Optimal Range |
|---|---|---|---|
| Creatinine / eGFR | CMP | CLINICALCreat 0.7–1.3 mg/dL / eGFR >60 | OPTIMALCreat 0.8–1.1 / eGFR >90 |
| Cystatin C Sensitive kidney marker | Serum Cystatin C | CLINICAL0.5–1.0 mg/L | OPTIMAL<0.7 mg/L |
| AST / ALT | CMP | CLINICALAST 10–40 / ALT 7–56 U/L | OPTIMALAST <26 / ALT <26 U/L |
| CBC | Complete Blood Count | CLINICALStandard lab ranges | OPTIMALMid-range; WBC 4.5–6.0 |
| Variable | Recommendation | Why |
|---|---|---|
| Frequency | Daily (7×/week) | SS-31 has a very short plasma half-life (~30 min). Daily dosing maintains mitochondrial cardiolipin protection continuously. Clinical trials all used daily dosing. |
| Fasted vs Fed | ~ Either acceptable | SS-31's mechanism is not insulin-dependent. It goes directly to mitochondria regardless of metabolic state. Fasted AM is conventional but no strong preference in the data. |
| Morning (AM) | ✓ Preferred | Morning dosing aligns with circadian mitochondrial activity peaks and ensures cardioprotection is active during the metabolically active daytime period. |
| Pre-exercise | ✓ Strongly considered | Dosing 20–30 min before training maximizes mitochondrial protection during the oxidative stress of exercise — directly aligning with SS-31's core mechanism. |
| Wait to eat | ~ Not critical | No evidence that food intake affects absorption or efficacy. Eat normally after injection. |