The short version of copper(II) complex fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-07-26 and is reviewed periodically as new material appears.
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.
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.
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 |
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 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.
GHK-Cu is the copper-binding complex formed by the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The free peptide is usually written as GHK, and the complex is written as GHK-Cu or Cu-GHK. The sequence was identified in human plasma and later detected in saliva and urine. Its name comes from the single-letter codes of glycine, histidine and lysine. The complex is widely described as a naturally occurring carrier of copper in blood rather than as a free peptide with its own hormonal role.
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.
In 1996 Merck paid $1.8 million for polluting the air. New machines were installed to reduce smog emissions by 680,000 lb (310,000 kg) a year. In November 1993, Merck & Co. acquired Medco Containment Services for $6 billion. Merck & Co. spun Medco off ten years later. Merck's supply chain reduction programme has been referred to as an example of successful change. Merck reduced its number of global suppliers from 40,000 to less than 10,000 during the period from 1992 to 1997.
=== Enantiomers === Tianeptine is a racemic mixture of (R)- and (S)- enantiomers. The (S)- enantiomer is known as estianeptine. (R)-Tianeptine is a weak μ-opioid receptor agonist, while estianeptine is a peroxisome proliferator-activated receptor (PPAR) agonist.
where j is the position of the amino acid in the four-residue window. If p(t) exceeds an arbitrary cutoff value (originally 7.5e–3), the mean of the p(j)'s exceeds 1, and p(t) exceeds the alpha helix and beta sheet probabilities for that window, then a turn is predicted. If the first two conditions are met but the probability of a beta sheet p(b) exceeds p(t), then a sheet is predicted instead.
Sources: en.wikipedia.org
In 1747, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen is not properly formed, causing poor wound healing, bleeding of the gums, severe pain, and death; Portuguese and Spanish sailors had independently known about the disease they acquired and how it was reduced after eating oranges and vegetables such as yams and turnips. In 1753, Lind published his Treatise on the Scurvy, which recommended using lemons and limes to avoid scurvy, which was adopted by the British Royal Navy. This led to the nickname limey for British sailors. However, during the 19th century, limes grown in the West Indies were substituted for lemons; these were subsequently found to be much lower in vitamin C. As a result, Arctic expeditions continued to be plagued by scurvy and other deficiency diseases. In the early 20th century, when Robert Falcon Scott made his two expeditions to the Antarctic, the prevailing medical theory was that scurvy was caused by "tainted" canned food. In 1881, Russian medical doctor Nikolai Lunin studied the effects of scurvy at the University of Tartu. He fed mice an artificial mixture of all the separate constituents of milk known at that time, namely the proteins, fats, carbohydrates, and salts. The mice that received only the individual constituents died, while the mice fed by milk itself developed normally.
== Clinical significance == Dihydropteridine reductase deficiency is a defect in the regeneration of tetrahydrobiopterin. Many patients have significant developmental delays despite therapy, develop brain abnormalities, and are prone to sudden death. The reason is not completely clear, but might be related to the accumulation of dihydrobiopterin and abnormal metabolism of folic acid. Response to treatment is variable and the long-term and functional outcome is unknown. To provide a basis for improving the understanding of the epidemiology, genotype/phenotype correlation and outcome of these diseases their impact on the quality of life of patients, and for evaluating diagnostic and therapeutic strategies a patient registry was established by the noncommercial International Working Group on Neurotransmitter Related Disorders (iNTD). Dihydropteridine reductase deficiency is treated with tyrosine supplements, a controlled diet which is lacking in phenylalanine, well as supplementation of L-DOPA.
At a time of increasing cooperation between the Western Allies and the Soviet Union in the wake of the Nazi invasion of 1941, the influence of the Polish government-in-exile was seriously diminished by the death of Prime Minister Władysław Sikorski, its most capable leader, in a plane crash on 4 July 1943. Around that time, Polish-communist civilian and military organizations opposed to the government, led by Wanda Wasilewska and supported by Stalin, were formed in the Soviet Union. In July 1944, the Soviet Red Army and Soviet-controlled Polish People's Army entered the territory of future postwar Poland. In protracted fighting in 1944 and 1945, the Soviets and their Polish allies defeated and expelled the German army from Poland at a cost of over 600,000 Soviet soldiers lost.
The jalapeño is variously named huachinango, for the ripe red jalapeño, and chile gordo (meaning "fat chili pepper") also known as cuaresmeño. The name jalapeño is Spanish for "from Xalapa", the capital city of Veracruz, Mexico. Contrary to popular belief, the jalapeño pepper is not grown in or around Xalapa, but Vicente Jiménez invented the process of pickling and canning the peppers in Xalapa. Genetic analysis of Capsicum annuum places jalapeños as a distinct genetic clade with no close sisters that are not directly derived from jalapeños. Jalapeños were in use by the Aztecs prior to the Spanish conquest; Bernardino de Sahagún in the Florentine Codex writes of Aztec markets selling chipotles (smoked jalapeños) and mole made from chipotles, besides the sale of fresh chilies. The use of peppers in the Americas dates back thousands of years, including the practice of smoking some varieties of peppers in order to preserve them; further well preserved samples and genetic testing would be needed to determine the usage and existence of the jalapeño clade and pod type in the past.
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.