This is a working overview of Copper(II), written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-12 and is reviewed periodically as new material appears.
The sequence now called GHK was first reported in the early 1970s after isolation from human plasma, where it was noted to influence liver cell behavior in laboratory preparations. Later work described a copper-binding form and its activity in fibroblast and wound-model experiments. Review articles frequently group the substance with other copper peptides. Concentrations in blood appear to fall with age in several small surveys, although the reason for this trend is not settled. Whether such a decline carries functional consequences remains an open question.
Published work on GHK-Cu concentrates largely on cell culture systems rather than whole organisms. Frequently used endpoints include collagen synthesis, expression of matrix metalloproteinases, and migration of fibroblasts. Some reports describe antioxidant behavior, while others stress delivery of copper into cells. These mechanisms are proposed rather than demonstrated, and the relative weight of each pathway is unclear. Human trials are few and generally small, so laboratory findings should not be read as confirmed clinical results.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Copper(II) peptide complex | Peptide chain coordinated to a single metal ion |
| CAS number | 89030-95-5 | Indexed for the peptide-copper complex |
| Molecular formula | C14H22CuN6O4 | Approximate formula for a one-to-one complex |
| Appearance | Blue to violet solid | Color from copper d-d transitions |
| Solubility class | Freely soluble in water | Also dispersible in some polar solvents |
The International Nomenclature of Cosmetic Ingredients lists the substance as copper tripeptide-1, the name that appears on most topical product labels. Related designations include copper peptide and GHK-Cu, and the hyphenated form is common in research literature. In cosmetics the material is regulated as an ingredient rather than as a drug, so products may reach the market without evidence of the effects claimed for them. Whether those effects are clinically meaningful is an open question, since most supportive data come from laboratory work and small trials.
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.
Discovery of GHK is generally attributed to work in the 1970s that isolated a plasma factor influencing liver cell behavior. Subsequent studies identified the copper-binding tripeptide and its ability to chelate copper with high affinity. Early reports linked the complex to wound healing and tissue remodeling in animal models. The free peptide and the copper-bound form have different properties, so the two are distinguished in the literature. Whether endogenous GHK-Cu serves a single primary physiological role remains an open question.
The molecular weight and charge of GHK-Cu depend on the pH and the number of coordinated ligands. At neutral pH, the peptide typically binds one copper ion, but ternary complexes with other biomolecules can form. Spectroscopic methods such as electron paramagnetic resonance and circular dichroism are used to study the coordination environment. Reports on the exact geometry vary because the complex is dynamic in solution. Researchers often use synthetic GHK-Cu rather than extracted material to control stoichiometry and purity.
GHK-Cu is a coordination complex formed from the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide binds copper through its histidine imidazole nitrogen, the terminal amino group, and the deprotonated amide nitrogen. This arrangement creates a square-planar or distorted geometry around the metal center, depending on pH and the presence of competing ligands. The complex occurs naturally in human plasma, saliva, and urine at low concentrations, and its sequence is conserved across many vertebrate species.
Copper content is measured separately, since a peptide assay alone does not report the metal-to-peptide ratio. Elemental techniques such as inductively coupled plasma optical emission spectroscopy quantify copper after acid digestion of the sample. The result is compared with the theoretical value for a one-to-one complex, and a shortfall indicates free peptide or partial dissociation. Suppliers differ in how they state purity, as some quote peptide content and others quote the whole complex. A defined stoichiometry therefore requires both a peptide assay and a copper assay.
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.
Israel has used Palestinian children as human shields in Gaza in violation of Geneva conventions. Human rights groups have said that "even if Hamas were using human shields", Israel must still abide by international law, especially the principle of proportionality. In May 2023, before the beginning of the Gaza war, Defence for Children International – Palestine (DCIP) had already documented that five children had been used as human shields by the Israeli army since the beginning of that year, with two of the victims being 2-year-old twins. According to a 2024 Haaretz investigation based on many Israeli soldiers' testimony, Palestinian teenagers, adults, and occasionally elderly men are regularly used as human shields to explore the tunnel network in the Gaza Strip. These shawashim are dressed up, apart from sandshoes, to look like Israeli soldiers, handcuffed, blindfolded and, with a video camera attached to their bodies, sent into houses where Hamas combatants are suspected to hide, or into tunnels that might be booby-trapped. The practice is said to be widely known to IDF field commanders. Palestinians were used when neither sniffer dogs nor drones were available. An October 2024 investigation by CNN found that while the scale and scope of the practice was unknown, testimony from civilians and an Israeli soldier showed Israel's use of Palestinians as human shields was widespread across the Gaza Strip.
=== Classification === Stevens–Johnson syndrome (SJS) is a milder form of toxic epidermal necrolysis (TEN). These conditions were first recognized in 1922. A classification first published in 1993, that has been adopted as a consensus definition, identifies Stevens–Johnson syndrome, toxic epidermal necrolysis, and SJS/TEN overlap. All three are part of a spectrum of severe cutaneous reactions (SCAR) which affect skin and mucous membranes. The distinction between SJS, SJS/TEN overlap, and TEN is based on the type of lesions and the amount of the body surface area with blisters and erosions. It is agreed that the most reliable method to classify EM, SJS, and TEN is based on lesion morphology and extent of epidermal detachment. Blisters and erosions cover between 3% and 10% of the body in SJS, 11–30% in SJS/TEN overlap, and over 30% in TEN. The skin pattern most commonly associated with SJS is widespread, often joined or touching (confluent), papuric spots (macules) or flat small blisters or large blisters which may also join. These occur primarily on the torso. SJS, TEN, and SJS/TEN overlap can be mistaken for erythema multiforme. Erythema multiforme, which is also within the SCAR spectrum, differs in clinical pattern and etiology.
=== Dependency === Adrenal suppression will begin to occur if prednisone is taken for longer than seven days. Eventually, this may cause the body to temporarily lose the ability to manufacture natural corticosteroids (especially cortisol), which results in dependence on prednisone. For this reason, prednisone should not be abruptly stopped if taken for more than seven days; instead, the dosage should be gradually reduced. This weaning process may be over a few days if the course of prednisone is short but may take weeks or months if the patient had been on long-term treatment. Abrupt withdrawal may lead to an Addisonian crisis. For those on chronic therapy, alternate-day dosing may preserve adrenal function and thereby reduce side effects. Glucocorticoids act to inhibit feedback of both the hypothalamus, decreasing corticotropin-releasing hormone (CRH), and corticotrophs in the anterior pituitary gland, decreasing the amount of adrenocorticotropic hormone (ACTH). For this reason, glucocorticoid analogue drugs such as prednisone down-regulate the natural synthesis of glucocorticoids. This mechanism leads to dependence in a short time and can be dangerous if medications are withdrawn too quickly. The body must have time to begin synthesis of CRH and ACTH and for the adrenal glands to begin functioning normally again. Prednisone may start to result in the suppression of the hypothalamic–pituitary–adrenal (HPA) axis if used at doses 7–10 mg or higher for several weeks. This is approximately equal to the amount of endogenous cortisol produced by the body every day.
The new Sudetengau was treated as an "endangered borderland." Using the same borderland funding that Saxony and Bavaria had received since 1931, the German government flooded northern Bohemia with funds to boost social welfare aid and to reduce unemployment. However, Bohemian Germans soon complained that the German occupation had also brought inflation, a declining standard of living, and a new form of outside rule, as Altreich bureaucrats filled business and government positions in the Sudetengau.
Villa Erica (Heather Villa): suggesting a Romano-British origin Bellerīca: a medieval Latin word meaning 'dyehouse or tanhouse' Billers: a traditional name for watercress, for which Bilbrook in Somerset and Staffordshire are named. Watercress was farmed in Billericay springs during the 20th century. Although the precise etymology of the name is not known, England has places similarly named:
Sources: en.wikipedia.org
=== Osteoporosis === Vitamin K is required for the gamma-carboxylation of osteocalcin in bone. The risk of osteoporosis, assessed via bone mineral density and fractures, was not affected for people on warfarin therapy – a vitamin K antagonist. Studies investigating whether vitamin K supplementation reduces risk of bone fractures have shown mixed results.
=== Immunodeficiency === In individuals lacking functional HLA-DM molecules, improper antigen presentation occurs, resulting in unwanted immune responses or lack of a response when danger is present. This has been shown experimentally through mouse knockout models. There will be an increase of CLIP, instead of peptide, presentation on APC surfaces. This can result in autoimmunity, if a T cell receptors recognize CLIP as a harmful antigen. There could also be no protein presentation at all, resulting in a lack of immune response.
In 1974, a military coup overthrew the Estado Novo regime, and started the Carnation Revolution. This initiated the transition to democracy and the dissolution of Portugal's colonial empire, from the independence of the African colonies to the Handover of Macau in 1999. This period was marked by social, military, and political turmoil that culminated in street politics and violence and led Portugal to near civil war. The 1975 coup cleared the way for the approval of a new constitution and the holding of elections, beginning to subside tensions. After the revolution, in the late 1970s and throughout the 1980s, under the influence of new economic insights, Portugal set about dismantling socialist policies from that period and moving towards neoliberalism. In 1986, Portugal joined the European Economic Community (EEC), which introduced structural reforms. This led in the 1990s to considerable economic growth driven by credit-fuelled consumer spending and a sharp rise in private indebtedness. Together with the growth of the financial and non-tradable sectors, this contributed to macroeconomic imbalances and paved the way for economic stagnation after the 2000s. It ultimately led to the 2010–2014 Portuguese financial crisis resulted in an international bailout and intense austerity policies, causing lasting impacts such as young adults' employment insecurity.
=== Evolution and biogeography === The development of a phylogenetic approach to taxonomy suggested the Liliales formed some of the earliest monocots. Molecular analysis indicates that divergence amongst the Liliales probably occurred around 82 million years ago. The closest sister family to the Liliaceae are the Smilacaceae, with the Liliaceae separating 52 million years ago. Liliaceae thus arose during the Late Cretaceous to Early Paleogene periods. Major evolutionary clades include the Lilieae (Lilium, Fritillaria, Nomocharis, Cardiocrinum, Notholirion) from the Himalayas about 12 mya and the Tulipeae (Erythronium, Tulipa, Gagea) from East Asia at about the same time. The Medeoleae (Clintonia and Medeola) may have appeared in North America but were subsequently dispersed, as may have the Streptopoideae and Calochortoideae. Liliaceae fossils have been dated to the Paleogene and Cretaceous eras in the Antarctic. The Liliaceae probably arose as shade plants, with subsequent evolution to open areas including deciduous forest in the more open autumnal period, but then a return of some species (e.g. Cardiocrinum). This was accompanied by a shift from rhizomes to bulbs, to more showy flowers, the production of capsular fruit and narrower parallel-veined leaves. Again, some reversal to the broader reticulate-veined leaves occurred (e.g. Cardiocrinum).
forward genetics An experimental approach in molecular genetics in which a researcher starts with a specific known phenotype and attempts to determine the genetic basis of that phenotype by any of a variety of laboratory techniques, commonly by inducing random mutations in the organism's genome and then screening for changes in the phenotype of interest. Observed phenotypic changes are assumed to have resulted from the mutation(s) present in the screened sample, which can then be mapped to specific genomic loci and ultimately to one or more specific candidate genes. This methodology contrasts with reverse genetics, in which a specific gene or its gene product is individually manipulated in order to identify the gene's function.
Sources: en.wikipedia.org
Often this is done with drugs produced by catalytic reduction, hydrogenation, oxidation, or the like, producing strong derivatives of morphine and codeine. Many morphine derivatives can also be manufactured using thebaine or codeine as a starting material. Replacement of the N-methyl group of morphine with an N-phenylethyl group results in a product that is 18 times more powerful than morphine in its opiate agonist potency. Combining this modification with the replacement of the 6-hydroxyl with a 6-methylene group produces a compound some 1,443 times more potent than morphine, stronger than the Bentley compounds such as etorphine (M99, the Immobilon tranquilliser dart) by some measures. Closely related to morphine are the opioids morphine-N-oxide (genomorphine), which is a pharmaceutical that is no longer in common use; and pseudomorphine, an alkaloid that exists in opium, both of which form as degradation products of morphine. As a result of the extensive study and use of this molecule, more than 250 morphine derivatives (also counting codeine and related drugs) have been developed since the last quarter of the 19th century. These drugs range from 25% the analgesic strength of codeine (or slightly more than 2% of the strength of morphine) to several thousand times the strength of morphine, to powerful opioid antagonists, including naloxone (Narcan), naltrexone (Trexan), diprenorphine (M5050, the reversing agent for the Immobilon dart) and nalorphine (Nalline). Some opioid agonist-antagonists, partial agonists, and inverse agonists are also derived from morphine.
=== Animal === Microchimerism occurs in most pairs of twins in cattle. In cattle (and other bovines), the placentas of fraternal twins usually fuse and the twins share blood circulation, resulting in exchange of cell lines. If the twins are a male–female pair, then XX/XY microchimerism results, and male hormones partially masculinize the heifer (female), creating a martin heifer or freemartin. Freemartins appear female, but are infertile and so cannot be used for breeding or dairy production. Microchimerism provides a method of diagnosing the condition, because male genetic material can be detected in a blood sample.
Alternating copolymers possess two regularly alternating monomer residues: (AB)n. An example is the equimolar copolymer of styrene and maleic anhydride formed by free-radical chain-growth polymerization. A step-growth copolymer such as Nylon 66 can also be considered a strictly alternating copolymer of diamine and diacid residues, but is often described as a homopolymer with the dimeric residue of one amine and one acid as a repeat unit. Periodic copolymers have more than two species of monomer units in a regular sequence. Statistical copolymers have monomer residues arranged according to a statistical rule. A statistical copolymer in which the probability of finding a particular type of monomer residue at a particular point in the chain is independent of the types of surrounding monomer residue may be referred to as a truly random copolymer. For example, the chain-growth copolymer of vinyl chloride and vinyl acetate is random. Block copolymers have long sequences of different monomer units. Polymers with two or three blocks of two distinct chemical species (e.g., A and B) are called diblock copolymers and triblock copolymers, respectively. Polymers with three blocks, each of a different chemical species (e.g., A, B, and C) are termed triblock terpolymers. Graft or grafted copolymers contain side chains or branches whose repeat units have a different composition or configuration than the main chain. The branches are added on to a preformed main chain macromolecule. Monomers within a copolymer may be organized along the backbone in a variety of ways.
=== Metabolism === Among the many metabolic processes in which it participates, glutathione is required for the biosynthesis of leukotrienes and prostaglandins. It plays a role in cysteine storage. Glutathione enhances the function of citrulline as part of the nitric oxide cycle. It is a cofactor and acts on glutathione peroxidase. Glutathione facilitates metabolism of xenobiotics. Glutathione S-transferase enzymes catalyze its conjugation to lipophilic xenobiotics, facilitating their excretion or further metabolism. The conjugation process is illustrated by the metabolism of N-acetyl-p-benzoquinone imine (NAPQI). NAPQI is a reactive metabolite formed by the action of cytochrome P450 on paracetamol (acetaminophen). Glutathione conjugates to NAPQI, and the resulting ensemble is excreted. As a result of this reaction, cellular glutathione concentration tends to be depleted in the presence of acetaminophen.
Sources: en.wikipedia.org
It is the copper complex of the tripeptide glycyl-L-histidyl-lysine. The metal ion is held by the histidine imidazole group and the peptide N-terminus. Most research on it concerns skin and wound models.
The tripeptide was first isolated from human plasma and has also been reported in saliva and urine. Plasma levels appear to decline with age in some small studies. Those observations rest on limited sample sizes.
It is not authorized as a systemic medicine in most countries. Cosmetic preparations list it as an ingredient rather than an active pharmaceutical substance. Legal status therefore differs by jurisdiction.
GHK-Cu is a complex of the tripeptide glycyl-L-histidyl-L-lysine with copper(II). The peptide binds copper through its histidine residue and neighboring amide nitrogens, forming a stable coordination compound. It is studied as a research chemical and used in some cosmetic formulations.