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Molecular Identity And Discovery Background — Research Overview

By Editorial Desk · published 2025-12-25 · last reviewed 2026-02-01 · Faq

This is a working overview of extracellular matrix, written for readers who want more than a one-paragraph summary but less than a textbook.

This page was last updated on 2026-02-01 and is reviewed periodically as new material appears.

Molecular Identity and Discovery Background

GHK-Cu is the copper complex of the tripeptide glycyl-L-histidyl-L-lysine, a short sequence found naturally in human plasma, saliva and urine. Loren Pickart reported the isolation of the free peptide in 1973 while studying factors that influenced the growth of aged liver cells in culture. The peptide was later shown to bind copper(II) with high affinity, and the metal-bound form became the focus of most subsequent research. Its concentration in circulation declines markedly with age, a pattern that is well documented, though the physiological consequences of that decline remain debated.

The peptide portion consists of three amino acids: glycine, histidine and lysine. Copper(II) coordinates through the imidazole nitrogen of histidine, the alpha-amino group of glycine and a deprotonated amide nitrogen of the backbone, producing a roughly square-planar geometry. This arrangement gives the complex its characteristic blue-to-violet colour and helps it resist dissociation in water. Reported stability constants are high, although values differ between studies because of differences in ionic strength and measurement method.

Molecular Identity and Discovery

GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide was isolated from human plasma in the early 1970s by Loren Pickart, who observed that a plasma fraction from young donors stimulated growth in cultured liver cells. The copper-bound form is abbreviated GHK-Cu, while the metal-free peptide is written simply as GHK. In the research literature the complex also appears as copper tripeptide-1 and as glycyl-histidyl-lysine copper complex.

Copper(II) binds the peptide through four nitrogen donors: the terminal amino group, the imidazole nitrogen of histidine, and two deprotonated amide nitrogens of the peptide backbone. This tetradentate arrangement gives a roughly square-planar geometry, the thermodynamically favoured form near neutral pH. Because the amide nitrogens must lose a proton before they can coordinate, complex formation is strongly pH-dependent, and the fully coordinated species dominates only above mildly acidic conditions. Electronic transitions within the copper d orbital set produce the characteristic blue to violet colour in aqueous solution.

Ghk-cu at a glance

PropertyValueNotes
INCI nameCopper tripeptide-1Standard designation on cosmetic ingredient labels
Peptide sequenceGly-His-LysThree-residue ligand; binding occurs at the histidine side chain
Metal-to-peptide ratio1 to 1One copper(II) ion per peptide unit
AppearanceBlue to violet powderColour arises from copper-to-peptide electronic transitions
Water solubilityFreely solubleCommonly formulated in aqueous or water-alcohol systems

Mechanism and Evidence Base

Laboratory studies describe GHK-Cu as a source of copper that cells can take up, with reported effects on collagen, elastin, and glycosaminoglycan synthesis in cultured fibroblasts. The peptide also appears in wound-repair research, where it is linked to the activity of matrix metalloproteinases and their inhibitors. These observations come largely from cell and animal models. How directly the complex controls any single pathway in intact human skin remains an open question, and reported effects depend on concentration, vehicle, and exposure time.

Copper takes part in redox chemistry, and the same property that makes it useful in enzymes can generate reactive oxygen species when the ion is loosely bound. GHK chelates copper through imidazole, amino, and amide nitrogen donors, which reduces the amount of free copper in solution. Whether that chelation is protective, neutral, or harmful in a given tissue is not settled. Laboratory assays report both antioxidant and pro-oxidant behavior, depending on the conditions and the readout used.

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Storage Stability And Analytical Checks

Solid GHK-Cu is usually supplied as a lyophilized powder and is kept cold and dry. Moisture, light, and repeated temperature cycling shorten its useful life in the laboratory. In aqueous solution the complex undergoes slow hydrolysis of the peptide backbone and gradual loss of coordinated copper. Buffers containing strong chelators, such as EDTA, compete for the metal and strip it from the peptide. Working solutions are therefore prepared shortly before use, and leftover liquid is not returned to the stock container.

Identity and purity are established with a combination of chromatographic and spectroscopic techniques. Reversed-phase high-performance liquid chromatography separates the intact complex from peptide fragments and free copper, and the elution profile yields a purity estimate. Mass spectrometry gives the mass of the intact species and exposes degradation products. Ultraviolet-visible spectroscopy displays a broad absorption band in the visible region that is characteristic of the copper center. Nuclear magnetic resonance is less informative here, because the paramagnetic metal broadens signals and complicates spectral interpretation.

Background from the literature

=== Futtermittel === Viele Getreidesorten weisen einen zu geringen Gehalt einer essentiellen Aminosäure auf. Durch diesen Mangel an nur einer Aminosäure sinkt die Verwertbarkeit aller aufgenommenen Aminosäuren auf den durch die in zu geringer Menge enthaltene essentielle Aminosäure („limitierende Aminosäure“) bestimmten Wert; die biologische Wertigkeit ist reduziert. Der Nährwert des Getreides kann dann durch den gezielten Zusatz geringer Mengen jener essentiellen Aminosäuren, die darin defizitär sind, gesteigert werden. Der Zusatz von L-Tryptophan zu Mischfuttern ist in der Futtermittelindustrie verbreitet.

== Handelsnamen == Monopräparate Ardeydorm (D), Ardeytropin (D), Kalma (A, D), sowie ein Generikum (D) Kombinationspräparate AKE (D), Alvesin (D), Aminofusin (D), Aminomel (D, A), Aminomix (D, A), Aminopäd (D, A), Aminoplasmal (D, A), Aminosteril (D), Aminoven (D), Clinimix (D, A), Custodiol (D, A), Deltamin (D), Glamin (D), Glavcamin (A), Infesol (D), Intrafusin (D), Kabiven (D), Nephrotect (D), Nutriflex (D, A), OliClinomed (D, A), Pädamin (A), Parentamin (D), Periplasmal (D, A), Salviamin (D), SmofKabiven (A), StructoKabiven (D, A), Synthamin (D), Vamin (A), Vitromix (A)

== Literatur == Berg, Tymoczko, Stryer: Biochemie. 5. Auflage. Spektrum Akademischer Verlag, Heidelberg 2003, ISBN 3-8274-1303-6. Burger, Wachter: Hunnius Pharmazeutisches Wörterbuch. 7. Auflage. Walter de Gruyter, 1993, ISBN 3-11-013868-9.

Sources: de.wikipedia.org

Further detail

Als verzweigtkettige Aminosäuren (abgekürzt BCAA für englisch Branched-Chain Amino Acids) bezeichnet man die proteinogenen Aminosäuren Valin, Leucin und Isoleucin. Sie gehören zu den essentiellen Aminosäuren, können also vom Körper nicht selbst gebildet werden, sondern müssen mit der Nahrung zugeführt werden. Sie kommen in allen proteinhaltigen Nahrungsmitteln vor. Im Gegensatz zu anderen Aminosäuren werden verzweigtkettige Aminosäuren weniger in der Leber und mehr in anderen Geweben verstoffwechselt.

Sources: de.wikipedia.org

Frequently asked questions

What is GHK-Cu made of?

It is a complex of a three-amino-acid peptide, glycine, histidine and lysine, bound to a single copper(II) ion. The metal is held mainly by the histidine side chain and the peptide backbone. Most commercial material is supplied as an acetate salt rather than as the free complex.

When was GHK-Cu first described?

The free peptide was reported in 1973 by Loren Pickart, who isolated it from human plasma. Its copper-binding behaviour was characterised over the following years. The metal-bound form has been the subject of most later research.

Is GHK-Cu the same as copper tripeptide-1?

Yes. Copper tripeptide-1 is the name used in cosmetic ingredient labelling, while GHK-Cu is the shorthand found in the scientific literature. Both refer to the same peptide-copper complex, and the two terms are interchangeable in most technical documents.

What is GHK-Cu made of?

It consists of a three-amino-acid peptide, glycine-histidine-lysine, bound to one copper(II) ion. The peptide supplies four nitrogen donor atoms, and the resulting complex is stable in neutral aqueous solution. The metal-free peptide is usually called GHK.

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