GHRP-6
GHRP-6 is a synthetic hexapeptide growth hormone secretagogue, among the earliest GHRPs developed, that activates the ghrelin receptor to stimulate growth hormone release largely through hypothalamic mechanisms and is well known for strongly increasing appetite.
This page is a research-orientation summary, not a dosing guide. For anything beyond general background, read the primary literature or talk to a qualified clinician — specifics like amount, frequency, or administration aren't something we publish here.
What it does & how it works
GHRP-6 activates the growth hormone secretagogue receptor (GHS-R1a) on somatotrophs and in the hypothalamus, stimulating phosphatidylinositol turnover and calcium-dependent GH release from pituitary cells. Human studies in patients with hypothalamic-pituitary disconnection showed that GHRP-6's GH-releasing effect is substantially blunted when the hypothalamic-pituitary connection is severed, indicating its action depends heavily on intact hypothalamic GHRH input rather than being a purely direct pituitary effect. As a ghrelin receptor agonist, it also engages the same receptor pathway that drives ghrelin's orexigenic (appetite-stimulating) signaling in the hypothalamic arcuate nucleus.
Typical results seen in research
Controlled human studies show GHRP-6 reliably raises circulating GH, and also increases ACTH and cortisol more than ghrelin-receptor-selective peptides like ipamorelin; nocturnal administration studies additionally found it alters sleep architecture alongside stimulating GH, ACTH, and cortisol release. Its appetite-stimulating effect is well documented pharmacologically and mirrors that of endogenous ghrelin, mediated through the same receptor in feeding-regulatory brain centers.
How it’s commonly used
GHRP-6 is administered by subcutaneous injection in research settings, often studied in combination with a GHRH analog to produce synergistic GH release. It has no FDA-approved therapeutic indication and remains exclusively an investigational compound.
- Life Sciences · 1995 Growth hormone releasing peptide (GHRP-6) stimulates phosphatidylinositol (PI) turnover in human pituitary somatotroph cells
- Clinical Endocrinology · 1995 Blocked growth hormone-releasing peptide (GHRP-6)-induced GH secretion and absence of the synergic action of GHRP-6 plus GH-releasing hormone in patients with hypothalamopituitary disconnection: evidence that GHRP-6 main action is exerted at the hypothalamic level
- Neuroendocrinology · 1995 Growth hormone-releasing peptide-6 stimulates sleep, growth hormone, ACTH and cortisol release in normal man
Curated from published literature for research orientation. Not an exhaustive review, and not a substitute for reading primary sources.