GHK-Cu: a fifty-year copper-peptide research record, from Pickart 1973 to the 2024 fibrosis literature.

1973: the tripeptide that started the record

GHK-Cu is the copper(II) complex of glycyl-L-histidyl-L-lysine, a naturally occurring human tripeptide that Loren Pickart isolated from human plasma in 1973 ^[1]. The original observation was specific and odd: an albumin-bound serum factor from young donors caused aged human liver-tissue explants to resume protein synthesis at rates characteristic of younger tissue ^[1]. That factor turned out to be a three-amino-acid peptide — Gly-His-Lys — and its biology, in the body, runs through its capacity to bind a single Cu(II) ion at the histidine imidazole, the deprotonated glycyl-histidyl peptide-bond nitrogen, and the alpha-amino group of glycine.

Fifty years later the literature is one of the longer continuous arcs in peptide research. Plasma GHK declines roughly 2.5-fold from age 20 (~200 ng/mL) to age 60 (~80 ng/mL) ^[2], coinciding with the age-related loss of regenerative capacity that motivates the exogenous-GHK-Cu work that followed. Pickart's group, alongside independent investigators (Mulder, Leyden, Miller, Pyo, Campbell, Park, He, Czyrski), has accumulated a record across dermatology, hair-follicle biology, diabetic-wound healing, COPD lung tissue, fibrosis, and antioxidant chemistry.

What is GHK-Cu?

GHK-Cu is the copper(II) complex of the human tripeptide glycyl-L-histidyl-L-lysine — molecular weight 340.4 Da for the free peptide, 403.93 Da for the copper complex, CAS 89030-95-5 ^[3]. Endogenous GHK is found in human plasma, saliva, and urine. In cosmetic regulation the molecule is listed under the INCI name Copper Tripeptide-1.

What is GHK-Cu peptide used for?

GHK-Cu has been studied for tissue remodeling, collagen synthesis, wound repair, hair-follicle modulation, antioxidant defense, and gene-expression regulation ^[3][4]. Substantive human-trial evidence is dermatological and topical — facial-cream photoaging trials, post-CO2-laser regimens, and a multicenter placebo-controlled diabetic-foot-ulcer trial ^[5][6][7]. Systemic, longevity, and organ-regeneration claims rest largely on in-vitro and rodent data.

Is GHK-Cu the same as copper peptides?

GHK-Cu is one specific copper peptide — the most studied — but the category 'copper peptides' includes related complexes such as AHK-Cu (alanyl-histidyl-lysine copper) and various GHK-Cu derivatives studied alongside it in hair-follicle assays ^[8]. When the cosmetic industry says 'copper peptides,' GHK-Cu is almost always the molecule in question.

What is the GHK copper peptide?

The GHK copper peptide is a Cu(II)-binding tripeptide whose principal active form in vivo is GHK-Cu. The peptide acts as a high-affinity copper chaperone, ferrying Cu(II) into cells, where copper-dependent enzymes and copper-modulated transcription factors do the downstream work ^[3]. Connectivity Map screening showed GHK at sub-micromolar concentrations modulated 4,192 of 13,424 assayed human genes in cultured fibroblasts ^[4] — a transcriptome-wide effect that reframed the molecule from 'wound-healing peptide' to 'gene-modulating copper chaperone.'

Also known as Copper Tripeptide-1

Copper Tripeptide-1 is the INCI cosmetic-industry name for GHK-Cu — the same molecule under the standardized labeling convention used on cosmetic packaging ^[3]. Synonyms in the literature include Cu-GHK, GHK copper peptide, Glycyl-Histidyl-Lysine-Cu, and (collapsed to one token in some search engines) GHKCu.

GHK vs GHK-Cu

GHK is the free tripeptide glycyl-L-histidyl-L-lysine. GHK-Cu is the same tripeptide coordinated to a Cu(II) ion. Copper binding is what activates most of the documented biological effects — strong Cu(II) chelators such as bathocuproine, which strip the copper from GHK-Cu, abolish its actions on collagen synthesis, wound healing, and gene expression in published in-vitro assays ^[3]. Free GHK exists in plasma, but it acquires copper rapidly from circulating albumin.

Topical GHK-Cu serums in the literature

A topical GHK-Cu serum is an aqueous or emulsion preparation of the copper complex, typically formulated at 0.05–5% (w/w), evaluated in dermatology trials for fine-line depth, skin roughness, collagen density, and laxity endpoints ^[5][6]. The 12-week 71-woman facial-cream trial reported by Leyden et al. (2002) remains the most-cited topical-cosmetic endpoint in the corpus ^[5].

Where to read further

The full chronological reading sits on study references and the milestone-by-milestone analysis on the GHK-Cu mechanism of action page. For the dose ranges actually reported across published trials, see the GHK-Cu dosage digest. For the dermal-papilla and follicle work, see copper peptides hair. For irritation, side-effect, and barrier-disruption reports, see the frequently asked questions.