GHRP-2 — Research Dossier
Evidence grading
Class
GHS-R1a agonist
Synthetic hexapeptide ghrelin mimetic
GH potency
>max-dose GHRH
Head-to-head human pharmacology (Arvat et al. 1997)
FDA approval
None
Not approved for any indication
WADA status
Prohibited
Category S2 — GH secretagogues
GHRP-2 is one of the best-characterised synthetic growth hormone-releasing peptides, with GH release exceeding maximal-dose GHRH confirmed in controlled human pharmacology — and no approved indication or long-term safety dataset.
GHRP-2 is a synthetic hexapeptide growth hormone secretagogue that stimulates GH release by binding the ghrelin receptor (GHS-R1a) on pituitary somatotrophs — a mechanism distinct from, and complementary to, GHRH. It belongs to the GHRP family first characterised by Bowers and colleagues (Endocrinology, 1984) alongside GHRP-1, GHRP-6 and hexarelin.
It has been studied most extensively in Japan, where clinical trials produced detailed dose-response and pharmacokinetic data. Among traditional GHRPs it sits in the middle on hormonal selectivity — producing moderate cortisol and prolactin elevation, more than ipamorelin and less than hexarelin — and is among the better-characterised in terms of human appetite effects.
“Intravenous GHRP-2 produced GH responses exceeding maximal-dose GHRH in healthy young adults, with only slight prolactin and ACTH/cortisol stimulation, establishing its hormonal selectivity profile.”
— Arvat E et al., Eur J Endocrinol 1997
Mechanism
GHRP-2 is a ghrelin mimetic: it activates GHS-R1a, stimulating pulsatile GH secretion while antagonising somatostatin. Among traditional GHRPs it shows intermediate selectivity — moderate cortisol and prolactin elevation (more than ipamorelin, less than hexarelin). Its ghrelin activity also drives appetite via hypothalamic NPY/AgRP signalling, though less strongly than GHRP-6. Animal studies report gastroprotective and anti-inflammatory properties including attenuation of cytokine and COX-2 responses.
Clinical evidence base
GH potency (well-established)
Arvat et al. (1997) conducted the definitive head-to-head comparison of GHRP-2, hexarelin, GHRH, TRH and hCRH in healthy young adults, establishing that intravenous GHRP-2 produced GH responses exceeding maximal-dose GHRH, with only slight prolactin and ACTH/cortisol stimulation. This paper defines the hormonal selectivity profile relative to other GHRPs.
Appetite (controlled human data)
Laferrère et al. (2005) showed in a controlled crossover study that GHRP-2 significantly increased caloric intake in healthy men, confirming orexigenic ghrelin-receptor activity in a human setting.
Cytoprotective (preclinical)
A body of preclinical work documents cytoprotective properties — cardioprotective, gastroprotective, and anti-inflammatory — consistent with GHS-R1a activation in non-pituitary tissues. These findings are preclinical and have not been replicated in controlled human efficacy trials.
Regulatory status and evidence grade
GHRP-2 is not approved by the FDA, MHRA, or EMA for any indication, despite extensive Japanese clinical study. As a GH secretagogue it is prohibited by WADA under category S2. Material supplied for laboratory work is research-use only.
Evidence grade: Phase II. GH-releasing and appetite-stimulating actions are confirmed in controlled human pharmacology. There are no completed registrational efficacy trials and long-term safety data are limited.
See also
References
- 1
Bowers CY, Momany FA, Reynolds GA, Hong A. On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone. Endocrinology. 1984.
- 2
Arvat E, Maccagno B, Ramunni J, et al. The GH-releasing activity of GHRP-2, hexarelin and GH-releasing hormone in humans. Eur J Endocrinol. 1997.
- 3
Laferrère B, Abraham C, Russell CD, Bowers CY. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. J Clin Endocrinol Metab. 2005.
- 4
Berlanga-Acosta J, Guillén-Nieto G, Rodríguez-Rodríguez N, et al. Synthetic growth hormone-releasing peptides (GHRPs): a historical appraisal of the evidences supporting their cytoprotective effects. Clin Med Insights Cardiol. 2017.
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