GHRP-6

Overview

GHRP-6 is a synthetic hexapeptide and one of the original growth hormone secretagogues — it predates the discovery of ghrelin itself, and was in fact one of the tools used to find the receptor that ghrelin turned out to occupy. It contains two D-amino acids, which slow enzymatic degradation. Unlike growth hormone-releasing hormone analogues such as sermorelin or CJC-1295, which act at the GHRH receptor, GHRP-6 acts at GHS-R1a, so the two classes are studied together in the literature for their combined effect. Because GHS-R1a is the ghrelin receptor, published work on GHRP-6 covers appetite and food intake as well as growth hormone release. A separate and substantial branch of the literature, much of it from Cuban groups, concerns cytoprotection in cardiac and other tissues through a CD36-dependent pathway that appears to be independent of growth hormone release. Human pharmacokinetic data exists in the indexed literature.

For research use only · Not FDA/EMA approved · Not for human consumption

Mechanism of Action

Published research describes GHRP-6 binding the growth hormone secretagogue receptor GHS-R1a on pituitary somatotrophs and in the hypothalamus, triggering a phospholipase C/IP₃ cascade, intracellular calcium release, and pulsatile growth hormone secretion. The literature reports that the effect is synergistic with GHRH rather than additive, because the two act through different receptors on the same cells, and that GHRP-6 also suppresses somatostatin tone. Through the same receptor in the hypothalamus, published studies describe stimulation of food intake — Yahashi and colleagues reported that GHRP-6 mimics ghrelin's effects on feeding and locomotor activity. A separate mechanism reported in the cytoprotection literature involves CD36 rather than GHS-R1a: Proulx and colleagues characterised azapeptide analogues of GHRP-6 as CD36 ligands, and Berlanga-Acosta and colleagues have reported cardioprotective effects in doxorubicin-induced injury. Delgado-Rubín de Célix and colleagues reported survival-factor activity in glutamate-induced excitotoxicity, and Granado and colleagues compared its effects with insulin on cell survival pathways.

For research use only · Not FDA/EMA approved · Not for human consumption

Key Research Areas

• Growth hormone release via GHS-R1a and synergy with GHRH
• Human pharmacokinetics in healthy volunteers
• Appetite and food intake through hypothalamic ghrelin signalling
• Cardioprotection in doxorubicin-induced and post-infarct models
• CD36-dependent cytoprotection distinct from GH release
• Neuronal survival in excitotoxicity models
• Growth hormone response in obese subjects
• Safety reviews of growth hormone secretagogues as a class

For research use only · Not FDA/EMA approved · Not for human consumption

Published Studies (8 cited)

For research use only · Not FDA/EMA approved · Not for human consumption

Dosage in Published Research

The published human pharmacokinetic study administered single intravenous doses in the microgram-per-kilogram range to healthy volunteers. Rodent protocols in the cytoprotection literature commonly use 100–400 μg/kg by intraperitoneal or subcutaneous route, given acutely or over multi-day courses. Because the growth hormone response and the CD36-mediated cytoprotective response are reported at different exposures, protocols differ substantially depending on which endpoint is under study. No standardised research protocol exists. All figures are cited from published literature for reference only.

For research use only · Not FDA/EMA approved · Not for human consumption

Storage & Handling

Store lyophilized powder at -20°C for long-term storage. Once reconstituted, store at 2–8°C and use within 14 days. Protect from light, moisture, and repeated freeze-thaw cycles. Handle under sterile laboratory conditions using appropriate PPE.

For research use only · Not FDA/EMA approved · Not for human consumption

Safety Profile (Literature Only)

The published human pharmacokinetic study reported the peptide as tolerated at the single doses investigated in healthy volunteers, and the class review by Sigalos and colleagues surveys the broader safety literature on growth hormone secretagogues. Published work notes that GHS-R1a agonism raises cortisol and prolactin to a greater degree than more selective secretagogues such as ipamorelin, which is a recurring point of comparison in the literature. No LD50 has been established in the indexed literature. This compound is for laboratory research use only.

For research use only · Not FDA/EMA approved · Not for human consumption