GHRP-6

GHRP-6 (Growth Hormone Releasing Peptide-6) is a first-generation synthetic hexapeptide that stimulates growth hormone release through activation of the ghrelin/GHS-R1a receptor. As one of the earliest GH secretagogues developed, it established the foundation for understanding GHRP pharmacology and led to the development of more selective compounds.

The compound produces significant GH release accompanied by notable appetite stimulation, a consequence of its ghrelin-mimetic activity at hypothalamic feeding centers. This orexigenic effect, mediated through the same receptor system as endogenous ghrelin, distinguishes GHRP-6 from more selective GH secretagogues and may be advantageous or limiting depending on research objectives.

GHRP-6 also stimulates gastric acid secretion and gut motility through peripheral GHS-R1a receptors, providing a research tool for investigating ghrelin's GI effects. Additionally, it produces modest elevations in cortisol, prolactin, and ACTH, reflecting its broader hypothalamic-pituitary activation profile.

Despite the development of more selective compounds, GHRP-6 remains valuable for research requiring robust GH stimulation combined with appetite and GI effects, and as a reference compound for comparing the selectivity profiles of newer GH secretagogues.