GHRP-6
GHRP-6 is one of the original synthetic growth hormone secretagogues — a compound whose pharmacology helped researchers identify the receptor it acts on, years before that receptor's natural hormone (ghrelin) was even discovered.
Not currently stocked by KYIN Peptides, but available to order — see availability below.
What Is GHRP-6?
GHRP-6 (Growth Hormone Releasing Peptide-6) is a synthetic hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) developed by Cyril Bowers and colleagues at Tulane University in the 1980s, as part of the original research program that established synthetic ghrelin-receptor agonists as a distinct class of growth hormone secretagogues. It binds the same receptor studied for Ipamorelin and Hexarelin — GHSR1a — but predates both by well over a decade, and its pharmacological profile is considerably less selective.
Research Focus
GHRP-6's defining research characteristic is what it does besides release growth hormone: it produces a pronounced, reliably reproduced increase in appetite (an orexigenic effect far stronger than later secretagogues), and it triggers meaningful off-target increases in cortisol, ACTH, and prolactin alongside GH release. This non-selective profile is precisely what later research programs set out to eliminate — see our Ipamorelin page and its discovery history for how Novo Nordisk's chemists used GHRP-6 as the pharmacological starting point for a more selective successor. See our GHRH & Growth Hormone research overview for how GHRP-6 fits alongside KYIN's stocked GH-axis peptides, or how Hexarelin and Sermorelin compare as other non-stocked compounds in this category.
Clinical & Preclinical Trial Data
GHRP-6 has a decades-long human research record dating to its original characterization by Bowers and colleagues (Endocrinology, 1984), which established it as a potent, reliably reproducible GH secretagogue in both animal and early human studies. Subsequent human research through the 1980s and 1990s consistently confirmed its non-selective hormonal profile — robust GH release accompanied by measurable cortisol, ACTH, and prolactin elevation — and its pronounced appetite-stimulating effect, properties that made it a widely used pharmacological research tool even as it was never developed into an approved drug.
GHRP-6's most lasting scientific contribution came indirectly: its receptor-binding activity was central to the 1996 cloning of the growth hormone secretagogue receptor (GHS-R1a) by Howard and colleagues (Science), which in turn enabled the 1999 discovery of ghrelin itself by Kojima and colleagues (Nature) as that receptor's endogenous ligand. GHRP-6 is not FDA-approved and has not been developed into a marketed drug.
Availability
GHRP-6 is not part of KYIN Peptides' standard catalogue, but it is available to order — contact us directly and we'll source it for you.
GHRP-6 questions
What is GHRP-6?
GHRP-6 is a synthetic hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) and ghrelin-receptor (GHSR1a) agonist — one of the earliest growth hormone secretagogues developed, predating later, more selective compounds like Ipamorelin.
How is GHRP-6 different from Ipamorelin?
GHRP-6 is non-selective: alongside growth hormone, it also triggers meaningful increases in cortisol, ACTH, and prolactin, and produces a pronounced appetite-stimulating (orexigenic) effect. Ipamorelin was developed specifically to reproduce GHRP-6's GH-releasing potency without those off-target hormonal effects.
Why is GHRP-6 historically significant in GH-axis research?
GHRP-6's pharmacology was instrumental in identifying the receptor it acts on. Its activity profile guided the 1996 cloning of the growth hormone secretagogue receptor (GHS-R1a), which in turn led to the 1999 discovery of ghrelin itself as that receptor's endogenous ligand.
Does KYIN Peptides sell GHRP-6?
Not as part of our standard catalogue, but yes — it's available to order. Contact us directly and we'll source it for you.
Interested in sourcing GHRP-6?
Contact us and we'll help you source it, or browse our stocked GH-axis peptides.