GHRP-6 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 originally called the GH secretagogue receptor, the hormone ghrelin is now considered the receptor’s natural endogenous ligand. Therefore, these GH secretagouges act as synthetic ghrelinmimetics.