Ipamorelin

Ipamorelin is a selective growth hormone secretagogue receptor (GHS-R1a) agonist — the same receptor targeted by endogenous ghrelin. The pentapeptide binds GHS-R1a on pituitary somatotrophs and hypothalamic neurons, triggering Gq-mediated phospholipase C activation and pulsatile growth hormone release.

The distinguishing pharmacological feature is selectivity. Unlike ghrelin and earlier GHRPs (GHRP-2, GHRP-6), ipamorelin does not significantly elevate cortisol, prolactin, or aldosterone at standard research doses. This selectivity is the reason ipamorelin is preferred in research protocols studying the GH axis without confounding cortisol response.

Co-administration with a GHRH analog (CJC-1295, tesamorelin) produces an additive GH response — GHRH increases the available pool of releasable GH while ipamorelin triggers the pulse — which is the mechanistic basis of the standard CJC-1295/Ipamorelin research blend.

Research Applications

• GH axis pharmacology research with low cortisol/prolactin confound.
• GHRH + GHRP additive response studies (paired with CJC-1295 or tesamorelin).
• Pulsatile GH release research in endocrine and sports-science models.