GHRP-2 — Growth Hormone Releasing Peptide — Growth Hormone

Overview

GHRP-2 (Growth Hormone Releasing Peptide-2, pralmorelin) is a synthetic hexapeptide that activates the growth hormone secretagogue receptor (GHSR-1a). It is one of the earliest and most studied GH-releasing peptides, having been used in clinical research since the 1990s. GHRP-2 produces robust GH release with less desensitization than hexarelin but more cortisol and prolactin elevation than ipamorelin. In clinical studies, GHRP-2 at 100-300 mcg subcutaneously produced peak GH levels of 20-60 ng/mL. GHRP-2 has been approved in Japan under the name Pralmorelin (GHRP Kaken 100) as a diagnostic agent for GH deficiency assessment. The compound stimulates appetite through ghrelin receptor activation, though less potently than GHRP-6. GHRP-2 is commonly combined with GHRH analogs (Mod GRF 1-29) for synergistic GH release. The combination approach is preferred as it produces physiologic pulsatile GH secretion while maximizing the GH response. GHRP-2 shows less receptor desensitization than hexarelin with chronic use, making it more suitable for sustained protocols, though cycling is still recommended for optimal efficacy.

Indications

• Approved (Japan): Diagnostic agent for GH deficiency (Pralmorelin/GHRP Kaken)
• Investigational: GH deficiency treatment
• Unapproved: GH optimization and anti-aging
• Unapproved: Body composition improvement

Mechanism of Action

GHRP-2 binds the ghrelin receptor (GHSR-1a) on pituitary somatotrophs and hypothalamic arcuate nucleus neurons

Dosing

Evidence Grade

GRADE C

Safety & Contraindications

• Cortisol and prolactin elevation (less than hexarelin, more than ipamorelin)
• Appetite stimulation (moderate — less than GHRP-6)
• Injection site reactions
• Fluid retention possible
• Not FDA-approved (approved in Japan for diagnostic use only)
• Research peptide quality varies