# GHK-Cu: A Fifty-Year Copper-Peptide Research Record (1973–2024)

> GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine, isolated by Pickart in 1973. A chronological editorial digest of the published literature.

_Eyebrow: TIMELINE · 1973 — 2024 · REV. 2026.05_

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

A chronological reading of the peer-reviewed GHK-Cu corpus — eleven milestone studies arrayed along a single connecting baseline, copper-binding events marked in oxidized copper, downstream-effect events marked in patina.

## 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](/#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](/references) and the milestone-by-milestone analysis on the [GHK-Cu mechanism of action](/research#mechanism) page. For the dose ranges actually reported across published trials, see the [GHK-Cu dosage](/dosage) digest. For the dermal-papilla and follicle work, see [copper peptides hair](/hair). For irritation, side-effect, and barrier-disruption reports, see the [frequently asked questions](/faq).

## References cited on this page

[1] Pickart L, Thaler MM. A tripeptide in human serum which prolongs the survival of normal liver cells and stimulates the growth of hepatoma cells. Nature New Biology. 1973;243(124):85-87. — https://pubmed.ncbi.nlm.nih.gov/4351778/
[2] Pickart L, Vasquez-Soltero JM, Margolina A. GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration. BioMed Research International. 2015;2015:648108. — https://pmc.ncbi.nlm.nih.gov/articles/PMC4508379/
[3] Pickart L, Margolina A. Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data. International Journal of Molecular Sciences. 2018;19(7):1987. — https://pmc.ncbi.nlm.nih.gov/articles/PMC6073405/
[4] Pickart L, Vasquez-Soltero JM, Margolina A. The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline. Brain Sciences. 2017;7(2):20. — https://pmc.ncbi.nlm.nih.gov/articles/PMC5332963/
[5] Leyden J, Stephens T, Finkey M, Appa Y, Barkovic S. Skin Care Benefits of Copper Peptide Containing Facial Cream. American Academy of Dermatology Annual Meeting Proceedings. 2002. — https://pmc.ncbi.nlm.nih.gov/articles/PMC4508379/
[6] Pickart L, Margolina A. Skin Regenerative and Anti-Cancer Actions of Copper Peptides. Cosmetics. 2018;5(2):29. — https://www.mdpi.com/2079-9284/5/2/29
[7] Mulder GD, Patt LM, Sanders L, Rosenstock J, Altman MI, Hanley ME, Duncan GW. Enhanced healing of ulcers in patients with diabetes by topical treatment with glycyl-L-histidyl-L-lysine copper. Wound Repair and Regeneration. 1994;2(4):259-269. — https://onlinelibrary.wiley.com/doi/10.1046/j.1524-475X.1994.20410.x
[8] Pyo HK, Yoo HG, Won CH, Lee SH, Kang YJ, Eun HC, Cho KH, Kim KH. Effect of Tripeptide-Copper Complexes on the Proliferation of Human Dermal Papilla Cells. Biological & Pharmaceutical Bulletin. 2007;30(4):834-838. — https://pubmed.ncbi.nlm.nih.gov/17409522/

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A horizontal-timeline reading of the GHK-Cu literature from Pickart 1973 to the 2024 fibrosis and liposomal-permeation work — eleven milestones scanned, copper-binding events marked separately from downstream effects, and signed by no clinic and no vendor.