A phospholipid found exclusively in the inner mitochondrial membrane, where it constitutes approximately 20% of the total lipid content. Cardiolipin’s unique four-chain structure anchors the electron transport chain complexes in their optimal configuration, facilitating efficient ATP production and maintaining membrane curvature.

Cardiolipin oxidation and remodeling defects are central to mitochondrial dysfunction in aging, heart failure, Barth syndrome, and neurodegenerative diseases. SS-31 (Elamipretide) binds selectively to cardiolipin, stabilizing its interaction with cytochrome c and preventing peroxidative damage. This mechanism makes SS-31 one of the few peptide compounds with a precisely defined molecular target—and it is the reason the compound is in advanced clinical trials rather than stuck in the preclinical phase that characterizes most research peptides.