GHRP-6
A potent ghrelin mimetic that strongly stimulates GH release and appetite. Unlike Ipamorelin, GHRP-6 also elevates cortisol and prolactin and causes extreme hunger, making it best suited for bulking phases.
Mechanism of Action
Mimics ghrelin by binding the GHS-R1a receptor on pituitary somatotroph cells, stimulating robust GH release. Also activates ghrelin receptors in the hypothalamus, producing intense appetite stimulation. Unlike more selective peptides, GHRP-6 also elevates ACTH (and consequently cortisol) and prolactin to some degree. Downstream anabolic effects mediated through the GH/IGF-1 axis.
Typical Dosing
⚠ Warning Flags
- •Extreme hunger — can make diet adherence very difficult
- •Elevates cortisol and prolactin (unlike Ipamorelin)
- •Water retention and bloating common
- •Best suited for mass-gaining phases where appetite is a limiting factor
Effect Profile
Side Effect Profile
Research Studies
On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone
Bowers CY et al. · 1991
First characterization of GHRP-6 demonstrating potent, dose-dependent GH release in humans.
Endocrine activities of ghrelin, a natural growth hormone secretagogue (GHS), in humans: comparison and interactions with hexarelin, a nonnatural peptidyl GHS, and GH-releasing hormone
Arvat E et al. · 1997
Compared ghrelin mimetics including GHRP-6 and characterized their distinct endocrine effects including appetite regulation.
Development of growth hormone secretagogues
Smith RG · 2005
Reviews the clinical development of GH secretagogues and their effects on GH secretion, appetite, and metabolism.