What Is GHRP-6?
GHRP-6 (Growth Hormone Releasing Peptide-6) is a synthetic hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂) and one of the first-generation GHRPs developed to study pulsatile growth hormone secretion. It acts as a functional ghrelin mimetic, binding the GHS-R1a receptor in the pituitary and hypothalamus.
Mechanism of Action
GHRP-6 stimulates GH release through two complementary pathways:
- Direct pituitary stimulation — binds GHS-R1a on somatotroph cells, triggering GH secretion
- Hypothalamic GHRH amplification — augments the natural GHRH pulse, producing a synergistic GH spike when combined with CJC-1295 or Sermorelin
Notably, GHRP-6 also stimulates ghrelin-mediated appetite — a feature that distinguishes it from second-generation GHRPs like Ipamorelin, which produces minimal appetite stimulation.
Research Findings
- GH pulse amplitude increases 7–15× above baseline in healthy male subjects at research doses
- Strong synergistic effect with GHRH analogues — combination produces significantly greater GH AUC than either compound alone
- Preclinical cardioprotective data: GHRP-6 demonstrated reduction in myocardial infarct size in ischaemia/reperfusion models
- Hepatoprotective effects observed in fibrosis models via TGF-β1 suppression
Classic Research Stack
The GHRP-6 + CJC-1295 (no DAC) combination is one of the most studied GH secretagogue stacks in peptide research. The GHRH analogue extends the GH pulse window while GHRP-6 amplifies its peak.
Related compounds: Ipamorelin, Hexarelin, Sermorelin, CJC-1295.