Journal September 16, 2026 5 min read

GHRP-6: Mechanism of Action

GHRP-6 is a synthetic hexapeptide growth hormone secretagogue that acts through the ghrelin receptor (GHSR-1a). This page outlines its receptor pharmacology and the tissue-specific mechanisms reported in animal and in vi

peptides-pro Editorial

Growth hormone-releasing peptide-6 (GHRP-6), also known as growth hormone-releasing protein-6, is a synthetic hexapeptide belonging to the growth hormone secretagogue (GHS) class. Its sequence is His-D-Trp-Ala-Trp-D-Phe-Lys-NH2, with a molecular formula of C46H56N12O6 and a molecular weight of approximately 873.0 Da. The peptide is a ghrelin analog and acts as an agonist at the growth hormone secretagogue receptor type 1a (GHSR-1a), the same receptor through which ghrelin signals [1][3][5].

The work reviewed here centres on GHSR-1a and its downstream endocrine, cardiovascular, immune, and metabolic effects across a range of preclinical models.

Research Studies

GHRP-6 and post-infarct ventricular remodeling in rats

In a permanent coronary ligation model of myocardial infarction in rats, GHRP-6 was administered for 7 days beginning after surgery. The study had previously determined 0.4 mg/kg as the minimum effective dose for enhancing inotropy based on echocardiographic parameters in healthy rats. In the infarct model, GHRP-6 treatment was associated with amelioration of post-infarct ventricular remodeling and systolic dysfunction compared with saline-treated infarcted controls [1].

GHRP-6 and endocrine and immune responses in Sparus aurata

GHRP-6 was included in aquafeeds at 500 µg/kg of feed and fed to Sparus aurata for 97 days. Following intraperitoneal injection with Incomplete Freund's adjuvant (IFA) at 100 µL/100 g fish, the endocrine and immune responses were assessed. The study reported that dietary GHRP-6 modulated these responses in the fish [2].

GHRP-6 and locomotor activity during acute nicotine withdrawal in rats

Male and female Wistar rats were treated with intraperitoneal nicotine at 2 mg/kg or saline twice daily for 7 days, then subjected to acute nicotine withdrawal. GHRP-6, acting through the same receptor as ghrelin, was investigated for its effects on horizontal and vertical activity. The study found that changes in locomotor activity observed during acute nicotine withdrawal could be attenuated by ghrelin and GHRP-6 [3].

GHRP-6 and human oocyte maturation in in vitro maturation culture media

In an in vitro study, 240 human germinal vesicle (GV) oocytes were cultured in varying concentrations of GHRP-6 to determine the most effective concentration for improving oocyte maturation and meiotic progression. The study assessed maturation rates during IVM culture [7].

GHRP-6 and food intake in broiler chickens

Intracerebroventricular (ICV) injection of LEAP-2 and its interaction with cannabinoid and ghrelin systems was studied in broiler chickens. In one experiment, chickens received ICV injections of saline or (D-Lys-3)-GHRP-6 at 0.5 nmol, a GHSR-1a antagonist, to examine effects on food intake [6].

GHRP-6 and the ghrelin-dopamine cascade in Flinders Sensitive Line rats

A novel butyrylcholinesterase inhibitor was evaluated in the Flinders Sensitive Line (FSL) rat model of major depressive disorder. Behavioural assessments included the forced swim test, sucrose preference test, and novel object recognition test. The study examined the role of the ghrelin-dopamine cascade, in which GHRP-6 acts as a ghrelin analog [8].

GHRP-6 and acute lung injury in preclinical models

In lipopolysaccharide (LPS) and zymosan (ZYM) induced lung injury models, GHRP-6 was reported to ameliorate acute lung injury and its subsequent evolvement to interstitial fibrosis. The study characterized the proliferative phase driving pulmonary fibrosis [9].

GHRP-6 and acute kidney injury via metabolic regulation

A GHRP-6 hydrogel was investigated for acute kidney injury therapy. Renal tubular epithelial cells (TECs) are highly susceptible to injury during AKI and have regenerative effects on renal recovery. The study targeted AKI-driven metabolic reprogramming of TECs, which plays a critical role in determining whether kidneys recover functionally or develop fibrosis [10].

GHRP-6 and anti-nervous necrosis virus activity

GHRP-6, a six-amino acid synthetic peptide acting as a ghrelin analog, has shown growth-promoting and immunomodulatory activities in several fish species. This study evaluated the effects of GHRP-6 against infection with nervous necrosis virus (NNV), an important pathogen in aquaculture [11].

GHRP-6 and ghrelin in ovarian hyperstimulation

Controlled ovarian hyperstimulation (COH) is essential in assisted reproductive technologies, although some studies have associated it with reduced reproductive success. Research has demonstrated that COH increases circulating ghrelin; however, its role in COH-induced alterations and the potential therapeutic impact of ghrelin analogs such as GHRP-6 remain under investigation [12].

GHRP-6 and performance-enhancing peptide landscape

Performance-enhancing drugs marketed as "research compounds" include unregulated peptides intended to modulate the growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis. GHRP-6 is among the growth hormone secretagogues commonly encountered in clinical practice and online self-administration protocols, alongside GHRH analogues and other GHS such as GHRP-2, hexarelin, and ipamorelin [5].

GHRP-6 and anterior cervical osteophyte-related dysphagia

A case report described a 62-year-old male ex-military recreational bodybuilder with a long-term history of growth hormone use who presented with cervicalgia and left shoulder pain. Imaging demonstrated multilevel degenerative changes including a prominent anterior osteophyte at C3-C4 with esophageal compression, and the patient reported intermittent dysphagia with larger food boluses. The role of systemic anabolic factors in osteophyte growth is poorly characterized [4].

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