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Hedi Raizer

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What is GHRP-6?

GHRP-6 is a synthetic hexapeptide growth hormone secretagogue and ghrelin receptor agonist used as a laboratory research compound. This page summarises the published preclinical evidence on its mechanisms, models and obs

peptides-pro Editorial

Growth hormone-releasing peptide-6 (GHRP-6) is a synthetic six-amino-acid peptide that acts as a growth hormone secretagogue and ghrelin receptor agonist. It is also referred to in the literature as growth hormone releasing protein-6 and is grouped with the growth hormone secretagogue (GHS) class of performance-enhancing peptides marketed as research compounds, alongside GHRP-2, hexarelin and ipamorelin [5]. The evidence block supplied for this page does not give a sequence, molecular formula or molecular weight for GHRP-6, so none are stated here.

The work summarised below centres on the growth hormone secretagogue receptor (GHSR), the receptor through which GHRP-6 and the endogenous peptide ghrelin both signal [3].

Research Studies

GHRP-6 and post-infarct ventricular remodelling in rats

In a permanent coronary ligation model of myocardial infarction in rats, GHRP-6 was administered for 7 days after surgery. The study had previously established 0.4 mg/kg as the minimum effective dose for enhancing inotropy in healthy rats, and used that dose in the infarct model. Animals were assigned to sham-operated, infarcted plus saline, and infarcted plus GHRP-6 groups, with echocardiographic assessment on day 7. The reported finding was that GHRP-6 ameliorated post-infarct ventricular remodelling and systolic dysfunction [1].

GHRP-6 and endocrine and immune responses in Sparus aurata

GHRP-6 was included in aquafeed at 500 µg/kg of feed and fed to gilthead sea bream (Sparus aurata) for 97 days. Fish were then injected intraperitoneally with saline or Incomplete Freund's adjuvant (IFA) at 100 µL per 100 g fish, and endocrine and immune responses were assessed. The study reported that dietary GHRP-6 modulated those responses following IFA treatment [2].

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

Male and female Wistar rats received intraperitoneal nicotine at 2 mg/kg or saline twice daily for 7 days, then underwent acute nicotine withdrawal. Ghrelin and GHRP-6 were tested for effects on horizontal and vertical activity. The reported finding was that changes in locomotor activity during acute withdrawal could be attenuated by ghrelin and GHRP-6 [3].

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

This was an in vitro study using 240 human germinal vesicle oocytes cultured in media containing varying concentrations of GHRP-6, with maturation rates assessed during culture. The stated aim was to determine the most effective concentration of GHRP-6, described as a ghrelin receptor agonist, in the culture medium [7].

GHRP-6 and food intake in broiler chickens

In a series of intracerebroventricular injection experiments in broiler chickens, one experiment used (D-Lys-3)-GHRP-6 at 0.5 nmol alongside saline and LEAP-2 at 0.75, 1.5 and 3 nmol, to examine interaction between LEAP-2 and the cannabinoid and ghrelin systems on food intake [6].

GHRP-6 and the ghrelin–dopamine cascade in a rat model of depression

A novel butyrylcholinesterase inhibitor was evaluated in Flinders Sensitive Line rats, a model of major depressive disorder, using the forced swim test, sucrose preference test and novel object recognition test. The study examined the role of the ghrelin–dopamine cascade in the observed antidepressant, pro-cognitive and anti-anhedonic effects [8].

GHRP-6 in acute lung injury and interstitial fibrosis

Work in lipopolysaccharide- and zymosan-induced lung injury biomodels has reported that GHRP-6 ameliorates acute lung injury and its subsequent progression to interstitial fibrosis [9].

GHRP-6 hydrogel in acute kidney injury

A GHRP-6 hydrogel formulation has been studied in acute kidney injury, with the reported focus on metabolic regulation in renal tubular epithelial cells and their regenerative role in renal recovery [10].

GHRP-6 and nervous necrosis virus infection

GHRP-6 has been evaluated for activity against nervous necrosis virus infection, a pathogen of importance in fish, in a study describing it as a six-amino-acid synthetic peptide acting as a ghrelin analog with growth-promoting and immunomodulatory activity in several fish species [11].

Ghrelin and embryo development after ovarian hyperstimulation

Separate work has reported that ghrelin impairs embryo development after controlled ovarian hyperstimulation, in a context where controlled ovarian hyperstimulation has been associated with increased circulating ghrelin [12].

Comparison of models and reported findings

Model or populationGHRP-6 exposureReported finding
Rats, permanent coronary ligation0.4 mg/kg, 7 days post-surgeryAmeliorated post-infarct ventricular remodelling and systolic dysfunction [1]
Sparus aurata, IFA treatment500 µg/kg of feed, 97 daysModulated endocrine and immune responses [2]
Wistar rats, acute nicotine withdrawalNot stated in the evidence blockAttenuated changes in locomotor activity [3]
Human germinal vesicle oocytes, in vitroVarying concentrations in IVM mediumConcentration–response for maturation assessed [7]
Broiler chickens, ICV injection(D-Lys-3)-GHRP-6 0.5 nmolUsed to probe LEAP-2, cannabinoid and ghrelin interaction on food intake [6]

GHRP-6 in the wider performance-enhancing peptide landscape

A review of performance-enhancing peptides marketed as research compounds lists GHRP-6 among the growth hormone secretagogues encountered in clinical practice and online self-administration protocols, alongside GHRH analogues such as sermorelin, tesamorelin and CJC-1295, other secretagogues such as GHRP-2, hexarelin and ipamorelin, the GH fragment AOD9604, and IGF-1 analogues [5].

Clinical case material involving long-term growth hormone use

A case report described a 62-year-old male former recreational bodybuilder with a long history of growth hormone use who presented with cervicalgia and shoulder pain, and was found on imaging to have multilevel degenerative changes including a prominent anterior cervical osteophyte at C3-C4 compressing the oesophagus, with intermittent dysphagia for larger food boluses [4]. The report concerns growth hormone rather than GHRP-6, and is included here only as clinical context for the anabolic-factor literature.

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This material is sold for laboratory research only, and we do not provide dosing or medical guidance. Anyone considering a compound for themselves should speak to a licensed clinician.

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