Do MOTS-c and SS-31 improve energy or exercise performance in humans, and how are they different?

MOTS-c is a mitochondria-encoded signaling peptide associated with metabolic stress responses. Researchers have shown that exercise raises endogenous MOTS-c in humans and that administering it can improve performance in mice. The first finding does not prove that injecting MOTS-c improves human exercise capacity. SS-31, also called elamipretide, instead targets the mitochondrial inner membrane and interacts with cardiolipin. Grouping both as “mitochondrial peptides” hides meaningful differences in mechanism, exposure and the populations actually studied.[1][2]

Elamipretide has been tested directly in people with primary mitochondrial myopathy. Although early studies generated encouraging signals, MMPOWER-3 did not significantly improve its primary walking-distance and fatigue endpoints overall. Later subgroup findings are not a substitute for a successful general performance trial. Neither those disease studies nor the MOTS-c mouse experiments establish better energy, endurance or hypertrophy in healthy lifters. The relevant question is whether the exact compound improves a meaningful outcome in a comparable human population, not whether it affects a pathway associated with ATP production.[1][2][3]