SS-31 (Elamipretide).

SS-31 binds cardiolipin and helps hold cristae structure and respiratory supercomplexes together, which is the environment ubiquinol shuttles electrons through. Structural support and electron carrier supply address different halves of the same membrane.

NAD precursors raise cofactor availability for the electron transport chain and sirtuin signalling, while SS-31 acts on cristae architecture rather than cofactor supply. The two touch separate limits on mitochondrial output.

PQQ signals through PGC-1alpha toward making new mitochondria while SS-31 works on the membrane structure of existing ones. Building capacity and maintaining capacity are different levers.

Urolithin A promotes mitophagy, the clearance of damaged mitochondria, while SS-31 supports the cardiolipin-dependent structure of those that remain. Clearance and maintenance are distinct arms of mitochondrial quality control.

Complex I carries FMN and complex II carries FAD, and both are built from riboflavin. Stabilising the membrane those complexes sit in does nothing if the flavin cofactors are short. This is textbook cofactor dependency rather than a tested combination.

Nearly every ATP-handling step runs on the Mg-ATP complex, not on free ATP. Any intervention aimed at oxidative phosphorylation depends on adequate magnesium for the output to be usable. The relationship is cofactor supply, not a demonstrated synergy.

Fatty acids cannot cross the inner membrane without the carnitine shuttle, and the carnitine-acylcarnitine translocase sits in that membrane alongside cardiolipin. A compound that binds cardiolipin and preserves membrane organisation and a compound that supplies the shuttle substrate address adjacent steps in fat oxidation. Human data on the pair are absent.

Cardiolipin is synthesised inside the mitochondrion from CDP-diacylglycerol and phosphatidylglycerol, and it is remodelled using acyl chains drawn from phosphatidylcholine by tafazzin. SS-31 binds the cardiolipin that already exists; phospholipid substrate supply is what determines how much there is to bind. The link is biosynthetic, not a tested pairing.

Mitochondrial creatine kinase is associated with the inner membrane and depends on local ATP output. Raising the creatine pool supports phosphate transfer downstream of oxidative phosphorylation, a different step from membrane stabilisation. Combination evidence does not exist.

Taurine-modified mitochondrial tRNA is needed to translate the subunits of the respiratory complexes, and taurine also influences membrane calcium handling. That places it upstream of the complexes whose organisation SS-31 preserves. This row is biochemistry, not clinical evidence.

Peroxidation of cardiolipin acyl chains is one route by which inner-membrane organisation is lost. A membrane-spanning carotenoid intercepts radicals in that same lipid phase, while SS-31 binds cardiolipin directly. The two target the same lipid from different angles; no human combination data exist.

Mitochondria import glutathione rather than making it in place, and that pool is what glutathione peroxidase uses to clear hydrogen peroxide from electron leak. SS-31 is described as lowering the peroxidase-like activity of cardiolipin-bound cytochrome c, which lowers one source of that stress. Both act on mitochondrial peroxide handling, at separate points.

Melatonin accumulates in the mitochondrial matrix and membranes at concentrations above plasma and reacts directly with oxidants. That overlaps in location with a cardiolipin-binding peptide. The overlap is anatomical and chemical; no trial of the pair is available.

Both of those dehydrogenase complexes sit in the mitochondrial matrix and cannot run without their lipoamide arm. Supplemental lipoic acid also enters the cellular thiol pool. This is a cofactor and redox relationship rather than a demonstrated combination effect.

Mitochondrial quality control has two arms, keeping existing organelles functional and clearing the ones that are not. A cardiolipin-binding peptide addresses the first; spermidine-induced autophagy addresses the second. Externalised cardiolipin is also a recognition signal in mitophagy, so the interaction could run either way and has not been measured in people.