A Peptide That Knows Where to Go

SS-31 (elamipretide) solves the targeting problem elegantly. Rather than attaching a delivery tag, it concentrates in mitochondria because of what it binds: cardiolipin, a phospholipid found only in the inner mitochondrial membrane. Bind cardiolipin, and you're in mitochondria — nowhere else in the cell has it.

Cardiolipin organizes the electron transport chain and stabilizes respiratory supercomplexes; oxidative damage to it cripples ATP production. SS-31 restores the cardiolipin-cytochrome c interaction, improves mitochondrial energetics, and reduces ROS. It has advanced to clinical trials — a level of development most longevity peptides never reach — though human results have been mixed. Members discuss it as the strongest example of organelle-targeted peptide design.