What Is Ghk Cu?

Overview

GHK-Cu (Copper Tripeptide-1) is a naturally occurring tripeptide complex consisting of the amino acids Glycyl-L-Histidyl-L-Lysine chelated to a copper(II) ion. First isolated from human plasma albumin in 1973 by Dr. Loren Pickart at UCSF.[1]

Origin: GHK is an endogenous peptide found in human plasma, saliva, and urine. It is released from the extracellular matrix during tissue injury — specifically cleaved from SPARC (Secreted Protein Acidic and Rich in Cysteine) and the alpha 2(I) chain of type I collagen.[2]

Age-related decline: Plasma concentration declines from approximately 200 ng/mL (10⁻⁷ M) at age 20 to roughly 80 ng/mL by age 60. This decline correlates with reduced tissue regeneration capacity.[2][3]

Structurally, GHK-Cu features a Cu(II) ion coordinated in a distorted square-planar pyramid by four nitrogen atoms: the amino-N of glycine, the amide-N of the Gly-His peptide bond, the imidazole-N of histidine, and an oxygen from water or a carboxyl group. The complex has a characteristic blue-purple color and a molecular weight of ~401.9 Da.[1]

GHK-Cu functions as a safe copper delivery vehicle by "redox silencing" the Cu(II) ion — preventing Fenton reaction toxicity that free copper would cause. Its binding constant (pKa 16.44) is similar to albumin's copper transport site (log₁₀ = 16.2), allowing GHK to exchange copper with albumin for intracellular delivery.[3]