GHRP-2

GHRP-2 belongs to the first generation of synthetic growth hormone secretagogues: six amino acids that share no structure with the stomach hormone ghrelin yet activate the same receptor, GHS-R1a, and thereby push the somatotroph cells of the pituitary into a pulse-like GH release.

From the research:

• In a head-to-head test on healthy adults, GHRP-2 and hexarelin produced a similarly strong, dose-dependent GH response that exceeded GHRH; prolactin, ACTH and cortisol climbed slightly as well (1997).
• Seven healthy men ate 35.9% more on average during a GHRP-2 infusion than during saline. The hunger effect of ghrelin can therefore be reproduced with the peptide (2005).
• In 15 children with short stature, intranasal dosing raised height velocity from 3.7 cm to 6.1 cm a year after six months without any change in IGF-1 (1997).
• The 1998 review places the GHRP class among compounds that act on hypothalamus and pituitary at the same time and probably imitate a natural hormone that was still unknown then. Ghrelin was only discovered in 1999.

In animal models GHRP-2 ranks among the most potent members of its family. The half-life is around 15 to 60 minutes, so the effect is brief. Compared with selective ipamorelin the profile is broader: besides GH, cortisol and prolactin move moderately, which is why many study designs now switch to ipamorelin and keep GHRP-2 for comparisons and potency questions. The compound's history goes back to the 1990s.

The evidence consists of short studies and user reports; long-term human data do not exist. Observed:

• Injection-site reactions: redness, pressure, short-lived irritation.
• Fluid retention, tingling or numbness in the hands, described for all GH secretagogues as dose-dependent and reversible.
• A moderate rise in cortisol and prolactin plus noticeably more hunger, which is the difference from selective ipamorelin.
• Higher fasting glucose and temporarily reduced insulin sensitivity as a consequence of raised GH levels.

This summary is no substitute for medical advice.

• Growth hormone-releasing peptide (GHRP) - review of the class and its dual site of action.
• Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men - infusion study on food intake in seven men.
• Treatment effects of intranasal growth hormone releasing peptide-2 in children with short stature - six months of intranasal dosing in 15 children.