Function
While GHRP-6 is used experimentally to produce strong GH surges and hyperphagia, allowing investigation of GH-dependent anabolism and energy-balance regulation2030, SS-31 improves mitochondrial bioenergetics, reduces oxidative stress, and shows protective effects in models of ischemia-reperfusion, neurodegeneration, and other mitochondrial disorders4637137.
Mechanism
While GHRP-6 works as a first-generation synthetic hexapeptide ghrelin mimetic that potently stimulates GH release and markedly increases appetite via GHSR-1a activation in hypothalamus and pituitary203096, 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.