GHRP-2

GHRP-2 activates the growth hormone secretagogue receptor (GHSR1a) with high affinity, stimulating GH release from pituitary somatotrophs. It is the most potent peptide-based GHSR1a agonist in the GHRP series. GHRP-2 stimulates GH release through direct pituitary action and through hypothalamic effects including somatostatin suppression and stimulation of endogenous GHRH release. The mechanism also involves amplification of GH pulse amplitude without significantly altering pulse frequency. Like other GHRP compounds, GHRP-2 activates appetite circuits via hypothalamic GHSR1a, though the appetite-stimulating effect may be less pronounced than with GHRP-6 at equipotent GH-releasing doses. GHRP-2 also stimulates ACTH and cortisol release, likely through CRH-dependent pathways, and elevates prolactin through dopamine-independent mechanisms.

Popovic et al. (2004) compared GHRP-2, GHRP-6, and GHRH as diagnostic tools for adult GH deficiency, finding GHRP-2 to be the most potent GH releaser with diagnostic accuracy comparable to the insulin tolerance test. Ghigo et al. (1998) reviewed the GHRP family and confirmed GHRP-2 as the most potent member. The compound is used clinically in Japan as pralmorelin (GHRP Kaken 100) for GH deficiency diagnosis. No large-scale RCTs have evaluated GHRP-2 for therapeutic endpoints such as body composition, functional performance, or anti-aging outcomes. The evidence base consists primarily of PK/PD studies, diagnostic accuracy data, and class-effect extrapolation from the broader GH secretagogue literature.

GHRP-2 is approved in Japan as pralmorelin (GHRP Kaken 100) for diagnostic evaluation of GH deficiency. It has no FDA or EMA approval. It is classified as a research chemical in most Western jurisdictions. WADA prohibits GHRP-2 in sport. Grey-market availability is widespread through peptide vendors online. Quality and purity of these products are not verified by any regulatory body.

IGF-1 levels at baseline and periodically to assess GH axis response. Cortisol (morning) and prolactin levels at baseline and during chronic use. Fasting glucose and HbA1c to assess metabolic effects. Body composition measurements if used for that purpose. Monitor for gynecomastia or menstrual changes related to prolactin elevation.

These are general considerations for clinical awareness and do not constitute prescriptive monitoring recommendations for any individual patient.

GHRP-2 is supplied as a lyophilized powder, typically in 5 mg or 10 mg vials. Reconstitute with bacteriostatic water. Refrigerate reconstituted solution at 2 to 8 degrees C and use within 2 to 4 weeks. Protect from heat and light. Administer subcutaneously, typically on an empty stomach for optimal GH response. The peptide is relatively stable in lyophilized form but degrades in solution over time.

1. 1

   RCT

   Comparison of GHRP-2, GHRP-6, and GHRH as Diagnostic Tools for GH Deficiency in Adults

   Popovic V, Pekic S, Pavlovic D, et al. (2004). European Journal of Endocrinology

   Key findings: GHRP-2 showed stronger GH-releasing potency than GHRP-6 and comparable diagnostic accuracy to insulin tolerance testing for GH deficiency. Both GHRPs stimulated cortisol and prolactin release.

   Limitations: Diagnostic study. Not designed to evaluate therapeutic outcomes.

2. 2

   review

   Growth Hormone Releasing Peptides: Clinical and Basic Aspects

   Ghigo E, Arvat E, Camanni F. (1998). Journal of Pediatric Endocrinology and Metabolism

   Key findings: Comprehensive review of GHRP-1, GHRP-2, GHRP-6, and hexarelin. Detailed comparison of potency, selectivity, and neuroendocrine effects. GHRP-2 identified as the most potent in the series.

   Limitations: Review based on early clinical data. Long-term safety profiles not established.