GHRP-6

Overview

GHRP-6 is a synthetic hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) growth hormone secretagogue and ghrelin receptor agonist. Developed by Bowers and Momany and first described in 1984, it was the first synthetic GHRP characterized and is defined by its pronounced appetite-stimulating effect — the strongest of any clinically studied GHRP. It has never been approved by the FDA or any regulatory agency and remains a research-only compound used off-label in the grey market.

Mechanism of Action

GHRP-6 binds the growth hormone secretagogue receptor 1a (GHSR-1a) on pituitary somatotrophs and hypothalamic neurons, mimicking endogenous ghrelin. Receptor activation (Gq/PLC/IP3) drives intracellular calcium release and pulsatile GH secretion while suppressing somatostatin tone. GHSR-1a activation in the arcuate nucleus strongly stimulates appetite — the hallmark feature of GHRP-6 and its defining difference from the selective GHRP ipamorelin. Compared with GHRP-2, GHRP-6 is generally less potent for raw GH output but more potent for appetite, and both produce modest transient elevations in ACTH, cortisol, and prolactin.

Research Summary

GHRP-6 was first characterized by Bowers, Momany, Reynolds, and Hong in Endocrinology (1984, PMID 6714155), establishing it as the first synthetic peptide to specifically release GH via a non-GHRH mechanism — a key tool in the later discovery of the ghrelin receptor. Ghigo et al. (European Journal of Endocrinology, 1997, PMID 9186261) reviewed the GHRP class and confirmed GH, ACTH/cortisol, and prolactin co-stimulation in humans. Berlanga et al. (Clinical Science, 2007, PMID 16989643) demonstrated ~78% infarct-mass reduction in a porcine myocardial infarction model via antioxidant mechanisms, and Berlanga-Acosta et al. (Clinical Medicine Insights: Cardiology, 2017, PMID 28469491) reviewed the cytoprotective GHRP literature across cardiac, neuronal, and hepatic tissues. GHRP-6 has never been approved for any clinical indication; its intense appetite stimulation and cortisol/prolactin co-release limit its clinical utility compared with ipamorelin.

Vendors selling GHRP-6

Scored vendors carrying GHRP-6, ranked by trust grade. Grades are computed from indexed Certificates of Analysis. Full $/mg pricing is on the comparison page.

Prescribers who offer GHRP-6

11 prescribers in our directory work with GHRP-6, each confirmed from their own website. Peptides like GHRP-6 require a prescription from a licensed provider.

Reported Side Effects

• Intense hunger within 15–20 minutes (hallmark feature)
• Water retention and bloating
• Facial flushing
• Lethargy or drowsiness
• Transient rise in ACTH, cortisol, and prolactin
• Tingling or numbness in extremities
• Injection-site reactions
• Insulin resistance with chronic use (theoretical)

Compare GHRP-6 with Others

Research References

• On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone (Bowers et al.) (1984)
• Growth hormone-releasing peptides (Ghigo et al.) (1997)
• Growth-hormone-releasing peptide 6 (GHRP6) prevents oxidant cytotoxicity and reduces myocardial necrosis in a model of acute myocardial infarction (Berlanga et al.) (2007)
• Synthetic Growth Hormone-Releasing Peptides (GHRPs): A Historical Appraisal of the Evidences Supporting Their Cytoprotective Effects (Berlanga-Acosta et al.) (2017)

Frequently asked questions

Has GHRP-6 been independently lab-tested?

Disclosed Labs has collected 13 Certificates of Analysis (COA) for GHRP-6 from 4 independent testing labs. 9 vendors have submitted material for testing. Products average 99.4% tested purity across the corpus. Full testing data is available at https://www.disclosedlabs.com/peptides/ghrp-6/testing.

What is the average purity of GHRP-6 on the market?

Based on 13 COAs analyzed by Disclosed Labs, GHRP-6 products average 99.4% (±0.3%) tested purity. Individual vendor results vary; see per-vendor COA data at https://www.disclosedlabs.com/peptides/ghrp-6/coas.

Where can researchers source GHRP-6?

7 vendors with Disclosed Labs trust grades currently list GHRP-6, including Ion Peptide, Real Peptides, Verified Peptides. Compare live prices and lab-verified COAs at https://www.disclosedlabs.com/prices/ghrp-6.

Which prescribers offer GHRP-6 with a prescription?

11 prescribers in the Disclosed Labs directory work with GHRP-6, each confirmed from their own website. GHRP-6 requires a prescription from a licensed provider. Browse them at https://www.disclosedlabs.com/prescribers?peptide=GHRP-6.

How does GHRP-6 work?

GHRP-6 binds the growth hormone secretagogue receptor 1a (GHSR-1a) on pituitary somatotrophs and hypothalamic neurons, mimicking endogenous ghrelin. Receptor activation (Gq/PLC/IP3) drives intracellular calcium release and pulsatile GH secretion while suppressing somatostatin tone. GHSR-1a activation in the arcuate nucleus strongly stimulates appetite — the hallmark feature of GHRP-6 and its defining difference from the selective GHRP ipamorelin. Compared with GHRP-2, GHRP-6 is generally less potent for raw GH output but more potent for appetite, and both produce modest transient elevations in ACTH, cortisol, and prolactin.

What does the research say about GHRP-6?

GHRP-6 was first characterized by Bowers, Momany, Reynolds, and Hong in Endocrinology (1984, PMID 6714155), establishing it as the first synthetic peptide to specifically release GH via a non-GHRH mechanism — a key tool in the later discovery of the ghrelin receptor. Ghigo et al. (European Journal of Endocrinology, 1997, PMID 9186261) reviewed the GHRP class and confirmed GH, ACTH/cortisol, and prolactin co-stimulation in humans. Berlanga et al. (Clinical Science, 2007, PMID 16989643) demonstrated ~78% infarct-mass reduction in a porcine myocardial infarction model via antioxidant mechanisms, and Berlanga-Acosta et al. (Clinical Medicine Insights: Cardiology, 2017, PMID 28469491) reviewed the cytoprotective GHRP literature across cardiac, neuronal, and hepatic tissues. GHRP-6 has never been approved for any clinical indication; its intense appetite stimulation and cortisol/prolactin co-release limit its clinical utility compared with ipamorelin.