The short version of glycyl-histidyl-lysine fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
The peptide was first isolated from human albumin in 1973 by Loren Pickart, who later described its copper-binding behavior. Early work linked the complex to wound healing and tissue remodeling. Plasma levels of GHK decline with age, a pattern that stimulated interest in topical and supplemental applications. Researchers have reported that the tripeptide influences collagen synthesis, antioxidant defense, and inflammatory signaling in cell and animal models. Human clinical evidence remains limited and often relies on small studies.
Commercial products list GHK-Cu as copper tripeptide-1, a cosmetic ingredient. Formulators value its blue color and water solubility, which allow incorporation into serums, creams, and masks. Regulatory treatment varies: in the United States it appears in cosmetics, while some jurisdictions classify certain claims as drug-like. The compound is not an approved drug for any indication. Studies continue to examine its effects on skin, hair, and wound repair, but dosage, delivery, and long-term safety questions remain open.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and copper(II). The peptide sequence consists of glycine, histidine, and lysine, and its imidazole and amino groups provide binding sites for the metal ion. In the complex, copper is held through nitrogen donors from the histidine side chain, the N-terminal amine, and deprotonated amide nitrogens. The resulting compound is intensely blue and water-soluble. It occurs naturally in human plasma, saliva, and urine at low concentrations.
GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine, a short sequence of three amino acids. The peptide was first isolated from human plasma in 1973 during research on factors that influence tissue repair in liver. Its ability to bind copper ions became a central point of interest because the metal changes the peptide's chemistry and its behaviour in laboratory systems. Today the compound appears in cosmetic formulations, cell-culture studies, and biochemistry literature under several names.
The peptide sequence places a histidine in the middle, and this residue dominates metal binding. Copper(II) coordinates through the imidazole nitrogen of histidine and the terminal amino group, forming a stable chelate ring system. Loss of the copper ion leaves the free tripeptide, which has different solubility and reactivity. This structural detail matters because assays that measure only the peptide backbone can miss whether copper is still bound to it.
Several names circulate for the same material, which complicates literature searches. Cosmetic ingredient lists often use copper tripeptide-1, while older biochemistry papers use glycyl-L-histidyl-lysine or its abbreviation GHK. The copper complex is sometimes written as GHK-Cu(II) to make the oxidation state explicit. Terminology is not fully standardized, so matching a compound across sources requires attention to the exact sequence, the counterion, and the stated copper content. Reviews that compare studies must account for these naming differences before drawing conclusions.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Copper(II) tripeptide complex | Contains glycyl-histidyl-lysine ligand |
| Peptide sequence | Gly-His-Lys | N-terminal glycine, C-terminal lysine |
| Molecular formula | C14H22CuN6O4 | Commonly cited for the 1:1 complex |
| Appearance | Blue to blue-violet solid | Color arises from copper d-d transitions |
| Solubility | Water-soluble | Also dissolves in some polar solvents |
Research interest in GHK-Cu centers on its ability to deliver copper and to influence cellular processes in laboratory models. In cell culture and animal studies, the complex has been linked to collagen synthesis, antioxidant enzyme activity, and expression of genes associated with tissue remodeling. These effects are not equivalent to proven clinical outcomes. The mechanisms proposed include copper transfer to cuproenzymes, modulation of growth factor signaling, and interactions with extracellular matrix components. How much of the observed activity depends on intact GHK-Cu versus free copper or free peptide is not fully resolved.
The compound entered scientific literature in the 1970s, when plasma factors with copper-binding activity were isolated and characterized. Later work expanded into wound healing, skin biology, and cosmetic formulation, where copper tripeptide-1 became a recognized ingredient name. Most published studies remain preclinical or small-scale, and findings are often reported in specialized dermatology or peptide journals. Regulatory treatment varies: some jurisdictions allow it as a cosmetic ingredient, while research-grade material is sold for laboratory use. Questions about optimal delivery, target tissues, and long-term effects continue to be investigated rather than settled.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide sequence is often abbreviated Gly-His-Lys, and the copper is bound through the histidine imidazole nitrogen and adjacent peptide nitrogens. The complex is frequently described as a 1:1 peptide-to-copper species. It occurs naturally in human plasma, saliva, and urine at low concentrations. Its endogenous levels have been reported to decline with age, although the precise physiological role of that change remains an open question.
Material described in research and cosmetic supply chains is typically a synthetic peptide supplied as a lyophilized powder. Purity is commonly reported through chromatographic separation, often at 95 percent or higher, while copper content is confirmed by separate elemental analysis. Batch variation in color and solubility can reflect residual counter-ions, moisture, or partial oxidation of the peptide. Because the complex is not a single regulatory entity, specifications differ between suppliers and are not standardized internationally.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide binds copper through its histidine imidazole nitrogen, its terminal amino group, and a deprotonated amide nitrogen, creating a stable chelate ring. The resulting complex carries a distinctive blue to blue-violet color, which arises from copper d-d electronic transitions. In the solid state it is usually handled as a powder, while in solution the complex can dissociate and re-form depending on pH and competing ligands. The name copper tripeptide-1 is widely used in ingredient listings.
The tripeptide was first isolated from a human plasma filtrate in 1973 during studies of tissue repair factors. Later work detected the free peptide and its copper complex in saliva, urine, and wound fluid, suggesting a natural role in tissue remodeling. Plasma concentrations reported in early literature decline with age, a pattern often cited in discussions of skin aging. Whether these endogenous levels are directly functional or largely incidental remains an open question. The peptide sequence is conserved across mammalian species.
The compound was first isolated from human plasma by the biochemist Loren Pickart in 1973. Early work identified it as a factor that altered the behavior of cultured liver cells, and later studies linked it to connective tissue and wound-related processes. Reported plasma concentrations fall markedly between roughly age twenty and age sixty, a pattern that generated interest in copper peptide biology. Whether that decline has functional consequences remains an open question, because differences observed across age groups do not by themselves establish causation. Research interest later expanded into cosmetic and tissue-culture settings.
Mechanistic accounts focus on how the complex delivers copper and how the released peptide interacts with the extracellular matrix. Copper is an essential cofactor for lysyl oxidase and other enzymes involved in collagen and elastin cross-linking, and GHK is one of several peptides able to carry the metal. Reported effects include altered gene expression in fibroblasts and changes in matrix metalloproteinase activity, although many of these findings come from cell culture rather than whole organisms. The relative contribution of the peptide backbone, the copper ion, and downstream copper metabolism is not fully resolved.
=== Legal definitions === In the US, the Food and Drug Administration does not allow a product to be referred to as "chocolate" if the product contains any of these ingredients. In the EU a product can be sold as chocolate if it contains up to 5% vegetable oil, and must be labeled as "family milk chocolate" rather than "milk chocolate" if it contains 20% milk. According to Canadian Food and Drug Regulations, a "chocolate product" is a food product that is sourced from at least one "cocoa product" and contains at least one of the following: "chocolate, bittersweet chocolate, semi-sweet chocolate, dark chocolate, sweet chocolate, milk chocolate, or white chocolate". A "cocoa product" is defined as a food product that is sourced from cocoa beans and contains "cocoa nibs, cocoa liquor, cocoa mass, unsweetened chocolate, bitter chocolate, chocolate liquor, cocoa, low-fat cocoa, cocoa powder, or low-fat cocoa powder".
Pipeline pig launchers and receivers are provided with a pig signaller (XA) to indicate that a pig has been launched or has arrived. Packaged items of equipment (compressors, diesel engines, electricity generators, etc) are fitted with local vendor supplied instrumentation. When equipment malfunctions a multivariable signal (UA) is sent to the control room. The fire and gas detection system comprises local sensors to detect the presence of gas, smoke or fire. These initiate alarms in the control room. Simultaneous detection of multiple sensors initiates action to start firewater pumps and close fire dampers in enclosed spaces. The petrochemical plant may have several levels of shutdown. A unit shutdown (USD) entails shutdown of one limited unit with the rest of the plant remaining in operation. A production shutdown (PSD) entails shutdown of the entire process plant. An emergency shutdown (ESD) entails complete shutdown of the plant. Older plant may have local control loops which operate pneumatic (3 – 15 psia) final element actuators. Sensors may also transmit electrical signals (4 – 20mA). Conversion between pneumatic and electrical signals is undertaken by P/I and I/P converters. Control of modern plant is based on a distributed control systems using fieldbus digital protocols.
==== Metabolic block ==== Nerve function depends on its blood supply. Arresting or inhibiting the blood supply can deprive nerve tissue of oxygen and other essential nutrients to induce a metabolic block, whereby the nerve is unable to function. This block is purely a physiologic problem such that the structure of the nerve is unchanged. If the metabolic block is short in duration, it is completely reversible with no permanent effects. An example of a metabolic block is when a limb "falls asleep" (temporary numbness, paresthesia, and weakness) due to the position of a limb that restricts blood flow. Complete ischema, such as the application of a tourniquet, is followed by hyperexcitability and then loss of nerve function over 60-90 minutes. The ischema is immediately reversible when the block is released, as long as the duration of ischema is not too long, such as 1-2 hours. The first sign of impairment to intraneural blood flow occurs in the epineural blood vessels at about 20-30mm Hg pressure. At pressures of 60-80mmHg there will be complete ischemia. A metabolic block can also be induced by stretching. In animal studies, venous statis was seen at an 8% stretch and at a 15% stretch the blood supply was completely arrested. It's a frequent occurrence that patients receiving a nerve decompression see an immediate improvement in their symptoms, and this is thought to be the restoration of blood flow after a metabolic block as other forms of functional nerve impairment such as neuropraxia and axonmetesis take longer to recover.
Sources: en.wikipedia.org
== Biology and medicine == Gamma-glutamyltransferase, an enzyme that catalyzes the reaction between a peptide and an amino acid Glutathione hydrolase, an enzyme that hydrolyzes glutathione A codon for the amino acid Glycine Germline gene therapy, to treat genetic diseases
== Reception == Ron Charles of The Washington Post praises Demon Copperhead as his "favorite novel of 2022" as it is "equal parts hilarious and heartbreaking, this is the story of an irrepressible boy nobody wants, but readers will love." Writing for The Guardian, Elizabeth Lowry contends that "while the task of modernising [Dickens's] novel is complicated by the fact that mores have shifted so radically since the mid-19th century … the ferocious critique of institutional poverty and its damaging effects on children is as pertinent as ever." In a starred review, Kirkus Reviews called the novel "An angry, powerful book seething with love and outrage for a community too often stereotyped or ignored."
On August 23, 2012, further results were published in the U.S. journal PLOS ONE in collaboration with Motoharu Seiki of the University of Tokyo Institute of Medical Science. By 2014, the technology had advanced to the stage of detecting Alzheimer’s-related substances directly from blood samples, and since April 2014, efforts under a new framework have been directed toward practical application.
== Contraindications == This product should not be used to cover a large area for anesthetic affect causing an adverse reaction. The liquid and other forms of Cetacaine should not be administered via injection or used under dentures, on eyes or with patients with a cholinesterase deficiency.
Sources: en.wikipedia.org
Brother Zachariah — formerly known as James "Jem" Carstairs, a Silent Brother, and the former parabatai of Will Herondale, who acts as a kind of uncle to James, Lucie and the others. He is also a first cousin to Cordelia and Alastair. Barbara Lightwood — The eldest child of Gideon Lightwood and Sophie Collins. Growing up, Barbara had the perfect Sight, the ability to see past glamours. She has an understanding with Oliver Hayward, whose family runs the York Institute. Barbara was very affectionate and protective over Thomas—to the point where he found it smothering—and was often considered more gentle than her sister. She was somewhat of a romantic, and wanted to become a dutiful wife rather than a strong Shadowhunter. During a demon attack in Regents Park, Barbara was bitten and collapsed. In her final moments, she was delirious and lashed out, clawing at Oliver who had been crying by her bedside. This unknowingly spread the infection to Oliver who fell ill and died shortly after. Thomas and the others dedicated themselves to not only making a cure but finding and putting an end to the demon attacks in her name. Eugenia Lightwood — The second child of Gideon Lightwood and Sophie Collins. Like Barbara, Eugenia was very affectionate and protective over Thomas, to the point where he found it smothering, and wants to become a dutiful wife rather than a strong Shadowhunter. She is considered stubborn and rebellious. Eugenia was seemingly dubbed "ruined" as she had apparently been found alone with a gentleman whom did not later propose to her.
==== United States ==== JRT is not an explicitly controlled substance in the United States. However, it could be considered a controlled substance under the Federal Analogue Act if intended for human consumption.
== External links == Receptors, Corticotropin-Releasing Hormone at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Overview of all the structural information available in the PDB for UniProt: Q60748 (Mouse Corticotropin-releasing factor receptor 2) at the PDBe-KB.
== Administrative divisions == The island of Negros is composed of 2 provinces, 1 highly urbanized city, 19 component cities, 38 municipalities and 1,219 barangays. Prior to the re-establishment of the Negros Island Region, Negros Occidental was designated as part of Western Visayas and Negros Oriental was designated as part of Central Visayas.
== Formal oxidation states for pyrite, marcasite, molybdenite and arsenopyrite == From the perspective of classical inorganic chemistry, which assigns formal oxidation states to each atom, pyrite and marcasite are probably best described as Fe2+[S2]2−. This formalism recognizes that the sulfur atoms in pyrite occur in pairs with clear S−S bonds. These persulfide [−S−S−] units can be viewed as derived from hydrogen disulfide, H2S2. Thus pyrite would be more descriptively called iron persulfide, not iron disulfide. In contrast, molybdenite, MoS2, features isolated sulfide S2− centers and the oxidation state of molybdenum is Mo4+. The mineral arsenopyrite has the formula FeAsS. Whereas pyrite has [S2]2− units, arsenopyrite has [AsS]3− units, formally derived from deprotonation of arsenothiol (H2AsSH). Analysis of classical oxidation states would recommend the description of arsenopyrite as Fe3+[AsS]3−.
Sources: en.wikipedia.org
GHK is the free tripeptide, while GHK-Cu includes a bound copper(II) ion. The copper complex is the form most often studied for skin and wound-related activity. The two names are sometimes used interchangeably in product labeling, but they refer to distinct chemical species.
Yes, it is found in human plasma, saliva, and urine. Its concentration in plasma tends to decrease with age. This natural presence is one reason researchers have investigated its role in tissue maintenance.
No, GHK-Cu is not an approved drug in major markets. It is widely used as a cosmetic ingredient, where it is listed under names such as copper tripeptide-1. Any therapeutic claims would require separate regulatory review.
The peptide is glycyl-L-histidyl-L-lysine, a three-amino-acid sequence commonly abbreviated GHK. It binds a single copper(II) ion under typical laboratory conditions. The free peptide and the copper complex are separate chemical species with different properties.