GHRP-6 - Frequently Asked Questions

It is a growth-hormone-releasing peptide and a synthetic hexapeptide, characterized in research models as an agonist of the growth-hormone-secretagogue receptor 1a (GHS-R1a), the ghrelin receptor. It is described as the prototypical, historical reference GHRP.

The sequence is His-D-Trp-Ala-Trp-D-Phe-Lys-NH2, a six-residue peptide with a C-terminal amide and two D-configuration residues (D-Trp and D-Phe).

In laboratory models GHRP-6 acts as an agonist at GHS-R1a (the ghrelin receptor) through a mechanism entirely distinct from growth-hormone-releasing hormone (GHRH), which signals through its own separate receptor.

GHS-R1a activation by GHRP-6 drives membrane phosphatidylinositol turnover, generating second messengers that activate protein kinase C and mobilize intracellular calcium stores in pituitary somatotroph models, dose-dependently releasing growth hormone in vitro and in vivo in the cited characterization.

The two D-amino acids, D-Trp and D-Phe, confer resistance to enzymatic degradation. Their non-natural configuration makes the peptide a poorer substrate for proteases, which is the structural basis for its comparative stability.

Molecular weight is 873.01 g/mol (ChemicalBook), molecular formula is C46H56N12O6, and the CAS number is 87616-84-0 (peptide.com).

Three documented areas: GHS-R1a agonist signaling (PI turnover, PKC, Ca2+); use as a reference compound for comparative GHRP studies; and ghrelin-receptor appetite-signaling models, all framed as receptor-level laboratory research.

Bowers, C. Y., Momany, F. A., Reynolds, G. A., and Hong, A. (1984), Endocrinology, On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone (DOI 10.1210/endo-114-5-1537; PMID 6714155).

Concentration equals peptide mass divided by solvent volume. Using the 873.01 g/mol molecular weight, a mass concentration is converted to molarity via moles = grams / 873.01 to set the working stock for in-vitro assays. This is a benchtop preparation principle, not a dosing protocol.

No. The source data does not include a numeric half-life, clearance, or degradation rate. The only peptide-specific stability statement is qualitative: the D-amino acids confer resistance to enzymatic degradation. Storage guidance beyond that reflects general research-peptide handling, not a GHRP-6 measurement.

As the historical reference compound, it anchors comparative secretagogue studies, meaning newer growth-hormone-releasing peptides are benchmarked against its well-defined GHS-R1a receptor target and signal-transduction profile.