GHK-Cu

GHK-Cu (sequence Gly-His-Lys complexed with Cu(II); CAS 89030-95-5; molecular formula C14H22N6O4Cu; molecular weight 401.91) is a naturally occurring tripeptide-copper(II) complex first isolated from human plasma in 1973 by Loren Pickart, then a graduate student at the University of California San Francisco. The free tripeptide GHK is present in human plasma at low micromolar concentrations and has very high affinity for Cu(II) (apparent dissociation constant in the picomolar range), forming the GHK-Cu complex that is the active species in many of the published bioassays. The compound has the most multidisciplinary published literature of any of the small bioactive peptides in research-grade circulation, with documented or suggested effects on wound healing, hair follicle activity, dermal collagen and elastin synthesis, anti-inflammatory cytokine modulation, modulation of more than 4,000 human genes (in cultured cells), and antioxidant defense. Plasma GHK-Cu concentrations decline with age, which is the rationale for many of the gerontology-focused claims. GHK is approved as a topical cosmetic ingredient in many jurisdictions and is widely used in dermatologic preparations. There is no FDA-approved IND for systemic GHK-Cu in any indication. The principal limitations on the strength of the evidence are heterogeneity in the dose, route, and formulation of GHK-Cu across the published preclinical literature; effects observed at one dose or route do not always translate to other contexts.