Octanoyl-DL-carnitine is a medium-chain acylcarnitine. It decreases the oxidation rate of the branched-chain 2-oxo acids 3-methyl-2-butanoate and 4-methyl-2-oxopentanoate in isolated rat muscle mitochondria in the presence of carnitine, but increases it in the absence of carnitine.{55274} Octanoyl-DL-carnitine, with malate, has been used as a mitochondrial respiration substrate to measure the effect of creatine on the respiration rate of isolated rat cardiac fibers exposed to increasing concentrations of ADP.{55275}