If you have been reading about copper(II) complex and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-02-27. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Gly-His-Lys | Three amino acids, histidine in the middle |
| Complex formula | C14H22CuN6O4 | One copper(II) ion per peptide |
| Molar mass (complex) | approx. 402.9 g/mol | Depends on counterion and hydration state |
| Appearance | Blue to blue-violet solid | Colour arises from copper coordination |
| Common synonyms | Copper tripeptide-1, GHK-Cu | Naming varies between disciplines |
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.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide backbone consists of glycine, histidine, and lysine joined in that order. Copper is held through the imidazole nitrogen of histidine and the alpha-amino group at the N-terminus, which together produce a square-planar arrangement around the metal center. The solid appears blue to violet, a color that originates from d-d electronic transitions within the copper coordination sphere. The complex is indexed under CAS number 89030-95-5.
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.
Copper binds to the peptide through the histidine imidazole nitrogen and the terminal amino group, forming a stable square-planar complex. Binding constants reported for copper(II) with GHK are high, so the peptide competes effectively for copper in solution. The complex absorbs visible light, which gives solutions a blue to violet colour. Whether the metal-free peptide has a distinct biological function of its own is still an open question; some work treats it mainly as a copper delivery vehicle, while other work reports peptide-specific effects.
The compound was first isolated from human plasma in the 1970s by Loren Pickart, who later described copper-binding activity in liver and other tissues. Early reports focused on its presence in blood and its ability to carry copper between proteins. Commercial and cosmetic use of the term 'copper peptide' has since broadened, and labels rarely distinguish GHK-Cu from other copper-binding fragments. This naming overlap makes literature searching harder, because cosmetic ingredient lists, supplier catalogues and laboratory papers use different vocabularies for the same molecule.
Bats are subject to predation from birds of prey, such as owls, hawks, and falcons. J. Rydell and J. R. Speakman argue that bats evolved nocturnality during the early Eocene period to avoid predators. Other zoologists find the evidence to be unclear and contradictory. Twenty-two (maybe twenty-three or twenty-four) species of tropical New World snakes are known to eat bats; they may wait for them at the entrances of their refuges or attack them inside. As are most mammals, bats are hosts to a number of internal and external parasites. Among ectoparasites, bats carry fleas and mites, as well as specific parasites such as bat bugs and bat flies (Nycteribiidae and Streblidae). Bats generally do not host lice, possibly due to high competition from other parasites, including the more specialised ones. Internal parasites of bats include tapeworms, roundworms and flukes.
=== Medications === Intravaginal administration is a route of administration where the medication is inserted into the vagina as a creme or tablet. Pharmacologically, this has the potential advantage of promoting therapeutic effects primarily in the vagina or nearby structures (such as the vaginal portion of cervix) with limited systemic adverse effects compared to other routes of administration. Medications used to ripen the cervix and induce labor are commonly administered via this route, as are estrogens, contraceptive agents, propranolol, and antifungals. Vaginal rings can also be used to deliver medication, including birth control in contraceptive vaginal rings. These are inserted into the vagina and provide continuous, low dose and consistent drug levels in the vagina and throughout the body. Before the baby emerges from the womb, an injection for pain control during childbirth may be administered through the vaginal wall and near the pudendal nerve. Because the pudendal nerve carries motor and sensory fibers that innervate the pelvic muscles, a pudendal nerve block relieves birth pain. The medicine does not harm the child, and is without significant complications.
=== Tawing === Tawing is a method that uses alum and other aluminium salts, generally in conjunction with binders such as egg yolk, flour, or other salts. The hide is tawed by soaking in a warm potash alum and salts solution, between 20 and 30 °C (68 and 86 °F). The process increases the hide's pliability, stretchability, softness, and quality. Then, the hide is air dried (crusted) for several weeks, which allows it to stabilize. The use of alum alone for tanning rawhides is not recommended, as it shrinks the surface area of the skin, making it thicker and hard to the touch. If alum is applied to the fur, it makes the fur dull and harsh.
While the method of chemical characterization of a daughter was successful for flerovium and livermorium, and the simpler structure of even–even nuclei made confirmation of oganesson (Z = 118) straightforward, there have been difficulties in establishing the congruence of decay chains from isotopes with odd protons, odd neutrons, or both. To get around this problem with hot fusion, the decay chains from which terminate in spontaneous fission instead of connecting to known nuclei as cold fusion allows, experiments were done in Dubna in 2015 to produce lighter isotopes of flerovium by reaction of 48Ca with 239Pu and 240Pu, particularly 283Fl, 284Fl, and 285Fl; the last had previously been characterized in the 242Pu(48Ca,5n)285Fl reaction at Lawrence Berkeley National Laboratory in 2010. 285Fl was more clearly characterized, while the new isotope 284Fl was found to undergo immediate spontaneous fission, and 283Fl was not observed. This lightest isotope may yet conceivably be produced in the cold fusion reaction 208Pb(76Ge,n)283Fl, which the team at RIKEN in Japan at one point considered investigating: this reaction is expected to have a higher cross-section of 200 fb than the "world record" low of 30 fb for 209Bi(70Zn,n)278Nh, the reaction which RIKEN used for the official discovery of element 113 (nihonium). Alternatively, it might be produced in future as a great-granddaughter of 295120, reachable in the 249Cf(50Ti,4n) reaction.
Sources: en.wikipedia.org
In late 2014, the Houthis repaired their relationship with Saleh, and with his help they took control of the capital city. The takeover prompted a Saudi-led military intervention to restore the internationally recognized government, leading to an ongoing civil war which included missile and drone attacks against Saudi Arabia and its ally the United Arab Emirates. Following the outbreak of the Gaza war, the Houthis began to fire missiles at Israel and to attack ships off Yemen's coast in the Red Sea, which they say is in solidarity with the Palestinians and aims to facilitate the entry of humanitarian aid into the Gaza Strip. The Houthi movement attracts followers in Yemen by portraying themselves as fighting for economic development and the end of the political marginalization of Zaydi Shias, as well as by promoting regional political–religious issues in its media. The Houthis have a complex relationship with Yemen's Sunnis; the movement has discriminated against Sunnis but has also allied with and recruited them. The Houthis aim to govern all of Yemen and support external movements against the United States, Israel, and Saudi Arabia. Because of the Houthis' ideological background, the conflict in Yemen is widely seen as a front of the Iran–Saudi Arabia proxy war.
== Impact == Since its initial publication, the monograph has come to be seen as a highly influential work in the field of mathematical biology. It serves as the essential text for most high level mathematical biology courses around the world, and is credited with transforming the field from a niche subject into a standard research area of applied mathematics.
=== Later === Many protest songs during the 1980s reflected general unease with escalating tensions between the Soviet Union and the United States brought on by Ronald Reagan's and Margaret Thatcher's hard line against the Soviets. For example, various musical artists wore military uniform-like costumes, as a reflection of the increased feeling of militarism seen in the 1980s. Songs symbolically showed the superpowers going to war, as in the Frankie Goes to Hollywood song "Two Tribes". This song's MTV music video featured caricatures of United States President Ronald Reagan and Soviet General Secretary Konstantin Chernenko in a wrestling match. Other songs expressed fear of World War III, as in the Sting song, "Russians", with lyrics such as "I don't subscribe to his [Reagan's or Khrushchev's] point of view" (that Reagan would protect Europe, or that Khrushchev would "bury" the West). Other examples include Sly Fox's "Let's go all the way", a song about "going all the way" to nuclear war, The Escape Club's "Wild, Wild West" with its various references to the Cold War and Fischer-Z's album "Red Skies over Paradise". The Genesis song "Land of Confusion" expressed a desire to make some sense out of the world, especially in relation to nuclear war. A number of punk rock bands from the 1980s attacked Cold War era politics, such as Reagan's and Thatcher's nuclear deterrence brinkmanship. A small sampling includes The Clash, Dead Kennedys, Government Issue, Fear, Suicidal Tendencies, Toxic Reasons, Reagan Youth, etc. Noted punk compilation P.E.A.C.E.
On October 31, a federal judge in Rhode Island cited the Administrative Procedure Act and temporarily ordered the Trump administration to continue SNAP funding. A second federal judge in Boston said the Trump administration's plan to stop SNAP funding during the shutdown was against the law, but did not order payments to resume. On November 7, Justice Ketanji Brown Jackson temporarily froze the lower court order requiring full payment of SNAP. ABC News stated, "at least nine states had already begun issuing SNAP benefits under the direction of the federal agency that operates SNAP," reportedly including California, Wisconsin, Kansas, Pennsylvania, New York, New Jersey, and Vermont. In early November, Trump called for ending the Senate's rule and tradition of the filibuster. On November 6, some Republican senators talked about making a "clean" Continuing Resolution one of the exceptions to the filibuster rule, but it's estimated that this change is unlikely. On November 9, the Senate achieved a 60-vote compromise of a "mini-bus" which will fund certain departments through next September and the rest of government through January 30. SNAP would be funded through September 2026. Senate Republicans agreed to have a vote on the Obamacare funding by the 2nd week of December. Eight Democrats voted with Republicans to end the shutdown. On November 12, the House passed the bill, 222 to 209. Trump then signed it into law.
=== 1973 Antitrust case over griseofulvin === In the 1960s, Glaxo Group Ltd. (Glaxo) and Imperial Chemical Industries (ICI) each owned patents covering various aspects of the antifungal drug griseofulvin. They created a patent pool by cross-licensing their patents, subject to express licensing restrictions that the chemical from which the "finished" form of the drug (tablets and capsules) was made must not be resold in bulk form, and they licensed other drug companies to sell the drug in finished form and subject to similar restrictions. The effect and intent of the bulk-sale restriction was to keep the drug chemical out of the hands of small companies that might act as price-cutters, and the effect was to maintain stable, uniform prices. The United States brought an antitrust suit against the two companies—United States v. Glaxo Group Ltd.—charging them with violation of the Sherman Act and also seeking to have the patents declared invalid. The trial court found that the defendants had engaged in several unlawful conspiracies, but dismissed the part of the suit seeking invalidation of patents and refused to grant as relief mandatory sales of the bulk drug chemical and compulsory licensing of the patents. The government appealed to the Supreme Court, which reversed, in United States v. Glaxo Group Ltd., 410 U.S. 52 (1973).
Sources: en.wikipedia.org
== Further reading == Hartonen, Kari; Laitinen, Totti; Riekkola, Marja-Liisa (2011). "Current instrumentation for aerosol mass spectrometry". TrAC Trends in Analytical Chemistry. 30 (9): 1486–1496. doi:10.1016/j.trac.2011.06.007. ISSN 0165-9936.
Elbasvir/grazoprevir, sold under the brand name Zepatier, is a fixed-dose combination for the treatment of hepatitis C, containing elbasvir (an inhibitor of hepatitis C virus's NS5A protein) and grazoprevir (an NS3/4A inhibitor). It is used to treat chronic hepatitis C virus (HCV) genotypes 1 or 4 infection in both treatment-naïve and treatment-experienced patients. Both elbasvir and grazoprevir were developed by Merck & Co. The US Food and Drug Administration (FDA) approved the drug in January 2016.
=== Heart disease === Abdominal obesity is typically associated with a statistically higher risk of heart disease, hypertension, insulin resistance, and type 2 diabetes (see below). With an increase in the waist to hip ratio and overall waist circumference the risk of death increases as well. Metabolic syndrome is associated with abdominal obesity, blood lipid disorders, inflammation, insulin resistance, type 2 diabetes, and an increased risk of developing cardiovascular disease. It is now generally believed that intra-abdominal fat is the depot that conveys the biggest health risk. Recent validation has concluded that total and regional body volume estimates correlate positively and significantly with biomarkers of cardiovascular risk and that BVI calculations correlate significantly with all biomarkers of cardiovascular risk. Abdominal obesity is linked with higher cardiovascular events among South Asian ethnic populations.
The particle size of the stationary phase is generally finer in flash column chromatography than in gravity column chromatography. For example, one of the most widely used silica gel grades in the former technique is mesh 230 – 400 (40 – 63 μm), while the latter technique typically requires mesh 70 – 230 (63 – 200 μm) silica gel.
Sources: en.wikipedia.org
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.
The sequence was identified in human plasma in 1973. Early work examined its presence in blood and its proposed role in tissue repair. The copper-binding property was characterized afterward and became the focus of much later research.
The tripeptide has been measured in human plasma and other biological fluids. Whether it circulates mainly as the copper complex or as the free peptide remains an open question. Natural concentrations are low and difficult to measure reliably.
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.