GHRP-6
Growth Hormone Releasing Peptide 6
An early GH secretagogue hexapeptide that strongly stimulates growth hormone and appetite.
Overview
GHRP-6 is a first-generation growth hormone releasing peptide. It reliably triggers GH release and markedly increases appetite through ghrelin receptor activation. Because it also raises cortisol and prolactin, later peptides like ipamorelin were developed for greater selectivity. It is not an approved drug.
Mechanism of action
Agonizes the ghrelin/GH secretagogue receptor (GHS-R1a) to stimulate GH release and appetite.
Key studies & citations
- Animal1991
On the actions of the growth hormone-releasing hexapeptide, GHRP
Bowers' foundational work: the hexapeptide His-DTrp-Ala-Trp-DPhe-Lys-NH2 (GHRP-6) releases GH through a dual hypothalamic and pituitary action via non-GHRH, non-opiate receptors in rats.
Endocrinology - In vitro1996
A receptor in pituitary and hypothalamus that functions in growth hormone release
Cloning of the G-protein-coupled growth hormone secretagogue receptor (GHS-R) in swine and human pituitary and hypothalamus, the target of GHRP-6 and related secretagogues.
Science - Animal1998
Ipamorelin, the first selective growth hormone secretagogue
Head-to-head pharmacology showing GHRP-6 and ipamorelin have similar GH-releasing potency in rat pituitary cells, rats and swine, with ipamorelin developed as the more selective successor.
European Journal of Endocrinology
Frequently asked questions
How does GHRP-6 differ from ipamorelin?
GHRP-6 strongly stimulates appetite and can raise cortisol and prolactin, while ipamorelin is more selective for GH release.