GHRP-6

GHRP-6 activates the growth hormone secretagogue receptor (GHSR1a, also known as the ghrelin receptor) on pituitary somatotroph cells, triggering GH release through phospholipase C and protein kinase C signaling pathways. Unlike GHRH, which acts through a different receptor and adenylyl cyclase, GHRP-6 amplifies GH pulses and can release GH even in the absence of GHRH stimulation. GHRP-6 also activates GHSR1a in the hypothalamus, suppressing somatostatin release and further enhancing GH secretion. The pronounced appetite stimulation results from GHSR1a activation in the arcuate nucleus and vagal afferent neurons. GHRP-6 lacks selectivity compared to ipamorelin: it stimulates ACTH and cortisol release (likely through hypothalamic CRH pathway activation) and increases prolactin levels.

Arvat et al. (2001) characterized the neuroendocrine profile of GHRP-6 in healthy volunteers, confirming potent GH release but also significant ACTH, cortisol, and prolactin stimulation. This lack of selectivity distinguishes GHRP-6 from ipamorelin, which releases GH without affecting other pituitary hormones. Berlanga et al. (2007) demonstrated wound healing promotion in diabetic rat models, with GHRP-6 accelerating closure through enhanced angiogenesis and reduced inflammation. No randomized controlled clinical trials have evaluated GHRP-6 for any therapeutic indication in humans. Its clinical evidence base rests on PK/PD studies, preclinical models, and extrapolation from the broader GH secretagogue class.

GHRP-6 has no regulatory approval in any jurisdiction for therapeutic use. It is classified as a research chemical. WADA prohibits GHRP-6 in sport under the GH-releasing factors category. It is available through grey-market peptide suppliers and some research chemical vendors. Products are not manufactured under GMP conditions. Some compounding pharmacies have prepared GHRP-6, though regulatory status varies by jurisdiction.

IGF-1 and GH levels to assess axis activation. Morning cortisol and ACTH if chronic use is planned, to detect sustained HPA axis stimulation. Prolactin levels at baseline and periodically. Fasting glucose and HbA1c given potential cortisol-mediated glucose effects. Body weight and composition tracking. Assessment of appetite changes and dietary intake.

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

GHRP-6 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. Susceptible to degradation from heat and light exposure. Administer subcutaneously, typically 2 to 3 times daily on an empty stomach for maximal GH response (food, particularly fats and carbohydrates, blunts the GH response).

1. 1

   RCT

   Growth Hormone-Releasing Peptide-6 Stimulates GH, ACTH, and Cortisol Release in Humans

   Arvat E, Maccario M, Di Vito L, et al. (2001). Journal of Clinical Endocrinology & Metabolism

   Key findings: GHRP-6 stimulated robust GH release but also significantly increased ACTH, cortisol, and prolactin levels, demonstrating lower selectivity compared to newer GH secretagogues.

   Limitations: PK/PD study in healthy volunteers. No efficacy endpoints measured.

2. 2

   preclinical

   GHRP-6 Promotes Wound Healing and Reduces Inflammation in Diabetic Rat Models

   Berlanga J, Cibrian D, Guillen I, et al. (2007). Growth Hormone & IGF Research

   Key findings: GHRP-6 accelerated wound healing in diabetic rats by promoting angiogenesis and reducing oxidative stress and inflammatory markers at the wound site.

   Limitations: Diabetic rat model. Wound healing application not explored in human trials.