GHRP-2

Research-Grade

GHRP-2 (also called pralmorelin or KP-102) is a synthetic hexapeptide (six amino acids: D-Ala-D-2Nal-Ala-Trp-D-Phe-Lys-NH2) and a second-generation growth-hormone-releasing peptide that improved substantially on GHRP-6's potency and side-effect profile. As a ghrelin-mimetic, it agonizes the growth hormone secretagogue receptor (GHSR-1a), triggering GH release through the phospholipase-C/IP3/calcium cascade in anterior pituitary somatotrophs. Its GH-releasing magnitude is among the highest in the GHRP class — comparable to or slightly exceeding ipamorelin on a per-dose basis, and consistently stronger than GHRP-6. However, unlike ipamorelin, GHRP-2 produces clinically meaningful elevations in prolactin (approximately 2-fold above baseline) and cortisol (20-30% above baseline) at GH-effective doses, along with moderate appetite stimulation via ghrelin-pathway activation. These off-target effects are the primary reason ipamorelin displaced GHRP-2 for chronic off-label GH protocols where hormonal selectivity is prioritized. Despite limited therapeutic development in the West, GHRP-2 achieved regulatory approval in Japan and South Korea as a diagnostic agent for GH-stimulation testing in suspected GH deficiency — marketed under the name pralmorelin. In this diagnostic context, a single intravenous bolus of 100 mcg provokes a measurable GH peak within 15-30 minutes, allowing endocrinologists to differentiate true GH deficiency from normal pituitary function. Clinical development for therapeutic GH-deficiency indications was pursued through phase-2 trials but did not advance to FDA approval, largely because orally-active GH secretagogues (such as MK-677/ibutamoren) and the more selective injectable ipamorelin offered better long-term profiles. GHRP-2 remains relevant as a research tool, a diagnostic standard in Asian clinical practice, and a reference compound for understanding GHRP pharmacology — but its combination of cortisol and prolactin elevation, appetite stimulation, and the availability of cleaner alternatives has confined its off-label use to niche applications.