Growth hormone releasing hexapeptide

Growth hormone releasing hexapeptide (GHRP6) is one of several synthetic met-enkephalin analogs that include unnatural D-amino acids, were developed for their growth hormone (GH) releasing activity and are called GH secretagogues. They lack opioid activity but are potent stimulators of GH release. These secretagogues are distinct from growth hormone releasing hormone (GHRH) in that they share no sequence relation and derive their function through action at a completely different receptor. This receptor was first called the GH secretagogue receptor, but now we know that the hormone ghrelin is this receptor's natural endogenous ligand and that these GH secetagouges act as synthetic mimetics of ghrelin.