Function
While AOD-9604 is studied as an anti-obesity peptide that can reduce weight gain and increase fat oxidation in obese animal models with generally neutral effects on IGF-1 and glucose metabolism in early human trials71111115, SS-31 improves mitochondrial bioenergetics, reduces oxidative stress, and shows protective effects in models of ischemia-reperfusion, neurodegeneration, and other mitochondrial disorders4637137.
Mechanism
While AOD-9604 works as a synthetic fragment of human growth hormone corresponding to residues 176–191 with an added N-terminal tyrosine, retaining lipolytic but not growth-promoting actions; proposed to stimulate lipolysis and inhibit lipogenesis in adipose tissue, partly via β3-adrenergic pathways without significantly activating the full GH receptor–IGF-1 axis6171111, SS-31 is a mitochondria-targeted tetrapeptide, d-Arg-dimethylTyr-Lys-Phe-NH2, that selectively binds cardiolipin in the inner mitochondrial membrane, stabilizing cristae structure, improving electron transport, and reducing ROS production4637137143.
Length and Sequence
AOD-9604 is 16 amino acids long, whereas SS-31 is shorter as it has a length of 4 amino acids. AOD-9604 is made up of a sequence of Tyrosine, Leucine, Arginine, Isoleucine, Valine, Glutamine, Cysteine, Arginine, Serine, Valine, Glutamic acid, Glycine, Serine, Cysteine, Glycine, Phenylalanine. SS-31 is made up of a sequence of Arginine, dimethylTyr, Lysine, Phenylalanine.