Both target mitochondria, and they sit at opposite ends of development. SS-31 went to a registered Phase 3 trial. MOTS-c has never been administered to humans in a published trial.
Side by side
| MOTS-c | SS-31 | |
|---|---|---|
| Class | Mitochondrial-derived peptide | Mitochondrial-targeted tetrapeptide |
| Status | Research compound | Investigational (Phase 3 as elamipretide) |
| Route | Subcutaneous injection | Subcutaneous injection |
| Typical vials | 5 mg, 10 mg | 10 mg, 50 mg |
| Dose range | 5 mg to 10 mg | 5 mg to 10 mg |
| Frequency | Weekly, often split | Once daily |
| Half-life | No human data | ~3 hours |
| Dosing unit | milligrams | milligrams |
Pharmacokinetics
No curves are shown, on purpose.
No published human pharmacokinetics for MOTS-c. Drawing one curve against an absent one would imply a comparison that cannot be made.
What the evidence supports
These grade how well each outcome has been studied in humans, never how well either compound works. A strong grade can sit on a negative result.
The strongest evidence for any claimed outcome is Human RCT for SS-31 and Human, observational for MOTS-c. That gap is the most important line on this page.
MOTS-c
| Outcome | Evidence |
|---|---|
| Endogenous levels correlate with fitness | Human, observational |
| Exercise capacity | Animal only |
| Metabolic homeostasis | Animal only |
| Any outcome from administration in humans | No data |
SS-31
| Outcome | Evidence |
|---|---|
| Barth syndrome | Human RCT |
| Dry age-related macular degeneration | Human RCT |
| Primary mitochondrial myopathy | Human RCT |
| Anti-aging or performance in healthy people | No data |
How to choose
SS-31 has the only real clinical program here
Elamipretide reached Phase 3 in mitochondrial myopathy. It missed its primary endpoint, which is a published negative result and more than most compounds on this site have.
MOTS-c human data is observational, not interventional
Circulating levels rise with exercise and correlate with metabolic measures. Nobody has published giving it to anyone.
The targets differ
SS-31 binds cardiolipin, a structural target in the inner membrane. MOTS-c acts through AMPK signaling.
At the syringe
At the default setup on each compound's own page, a 10 mg vial in 2 mL puts 50 mcg on every insulin unit, while a 10 mg vial in 2 mL puts 50 mcg on every unit. That is the number that decides whether a dose lands on a readable mark, and it is set by how much water goes in, not by the compound.