GHRP-2: A Potent Synthetic Growth Hormone Secretagogue in GHS-R1a Research
Research Use Only. This article is for scientific and educational reference only. All products are sold for research purposes and are not intended for human or animal consumption.
Overview
GHRP-2 (CAS 158861-67-7), or Growth Hormone Releasing Peptide-2, is a synthetic hexapeptide with the sequence D-Ala-D-β-Nal-Ala-Trp-D-Phe-Lys-NH₂ and a molecular weight of approximately 818 Da. It is a second-generation synthetic growth hormone secretagogue developed to improve upon GHRP-6, with greater GH-releasing potency and reduced appetite-stimulating effects.
GHRP-2 acts through the same GHS-R1a receptor as GHRP-6 and endogenous ghrelin, but its structural modifications confer higher binding affinity and a more favorable selectivity profile for research applications where appetite stimulation is an unwanted variable. It has been widely used in both preclinical and clinical research to characterize the ghrelin receptor system and its role in GH regulation.
Mechanism of Action
Like GHRP-6, GHRP-2 is a full agonist at the GHS-R1a receptor on pituitary somatotrophs. Receptor activation stimulates GH release through phospholipase C-mediated increases in intracellular calcium, a pathway distinct from the adenylyl cyclase mechanism used by GHRH. GHRP-2 also suppresses hypothalamic somatostatin release, removing inhibitory tone on pituitary GH secretion and amplifying the overall GH response.
The combination of GHRP-2 with GHRH or GHRH analogues (such as CJC-1295 or sermorelin) produces synergistic GH release that substantially exceeds the effect of either peptide alone. This synergy arises from the complementary mechanisms of the two receptor pathways and has been exploited in research protocols designed to maximize GH axis stimulation.
Key Research Findings
Clinical research has demonstrated that GHRP-2 produces dose-dependent increases in GH secretion, with peak GH responses typically 3–7 fold above baseline following intravenous administration. A study by Popovic et al. demonstrated that GHRP-2 combined with GHRH produced GH responses comparable to insulin tolerance testing, establishing its utility as a diagnostic tool for GH deficiency assessment.
Research comparing GHRP-2 and GHRP-6 has consistently found that GHRP-2 produces greater GH release per unit dose with less pronounced appetite stimulation, attributed to lower intrinsic efficacy at hypothalamic GHS-R1a receptors mediating feeding behavior. Studies in elderly subjects have shown that GHRP-2 can partially restore age-related decline in GH pulse amplitude, with associated improvements in IGF-1 levels and body composition parameters.
Chemical Properties
| Property | Value | |---|---| | Sequence | D-Ala-D-β-Nal-Ala-Trp-D-Phe-Lys-NH₂ | | Molecular Weight | ~818 Da | | CAS Number | 158861-67-7 | | Form | Lyophilized powder | | Purity (research grade) | ≥99% HPLC | | Storage | −20°C, protect from light |
Research Considerations
GHRP-2 is supplied as a lyophilized powder for research use. As with all GH secretagogues, GH responses are attenuated by hyperglycemia and elevated free fatty acids, and research protocols should standardize metabolic state prior to GH measurements. GHRP-2's higher potency relative to GHRP-6 means that dose selection is an important variable in study design.
Research Use Only. This article is for scientific and educational reference. All products are sold for research purposes only and are not intended for human or animal consumption.