GHRP (Growth Hormone Releasing Peptide)
Also known as: Growth Hormone Releasing Peptide
GHRPs are synthetic peptides that stimulate growth hormone release by activating the ghrelin receptor. Ipamorelin is a selective GHRP notable for triggering GH release without significant cortisol or prolactin elevation.
Overview
GHRPs work through a receptor pathway that is distinct from GHRH: they mimic ghrelin, a stomach-derived hormone that activates the GHS-R1a (growth hormone secretagogue receptor). This dual-pathway approach — combining a GHRH analogue with a GHRP — is studied as a way to amplify GH pulse magnitude by stimulating pituitary somatotrophs through two independent mechanisms simultaneously. Early GHRPs (GHRP-2, GHRP-6) caused notable increases in cortisol and prolactin alongside GH, limiting their research utility. Ipamorelin, a later-generation pentapeptide GHRP, is selective for GH release with minimal off-target hormonal effects, making it the most studied GHRP in modern research protocols.
Related Peptide Profiles
Frequently asked questions
Why is Ipamorelin preferred over older GHRPs?+
Ipamorelin is highly selective for GH release with minimal cortisol and prolactin elevation, side effects associated with earlier GHRPs like GHRP-6.
Do GHRPs work through the same receptor as GHRH?+
No. GHRPs act on the ghrelin receptor (GHS-R1a) while GHRH acts on the GHRH receptor. This is why stacking both types amplifies GH release beyond what either achieves alone.
Can GHRPs increase GH levels to supraphysiological levels?+
In animal studies, GHRPs can substantially elevate GH, but they work within the body's existing feedback systems and require functioning pituitary somatotrophs to produce GH.