Copper(II) is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H24N6O4 | Free tripeptide, without copper |
| Molecular weight | About 340 g/mol | Peptide portion only |
| Appearance | Blue to violet powder | Color from copper coordination |
| Solubility | Soluble in water | pH influences dissolution |
| Common synonyms | Copper tripeptide-1, Cu-GHK | Seen on ingredient labels |
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 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.
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.
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.
Bismuth is included in bismuth strontium calcium copper oxide, which is a group of similar superconducting compounds discovered in 1988 that exhibit the highest superconducting transition temperatures. Bismuth telluride is a semiconductor and an excellent thermoelectric material. Bi2Te3 diodes are used in mobile refrigerators, CPU coolers, and as detectors in infrared spectrophotometers. Bismuth oxide, in its delta form, is a solid electrolyte for oxygen. This form normally breaks down below a high-temperature threshold, but can be electrodeposited well below this temperature in a highly alkaline solution. Bismuth germanate is a scintillator, widely used in X-ray and gamma ray detectors. Bismuth vanadate is an opaque yellow pigment used by some artists' oil, acrylic, and watercolor paint companies, primarily as a replacement for the more toxic cadmium sulfide yellows in the greenish-yellow (lemon) to orange-toned yellow range. It performs practically identically to the cadmium pigments, such as in terms of resistance to degradation from UV exposure, opacity, tinting strength, and lack of reactivity when mixed with other pigments. The most commonly used variety by artists' paint makers is lemon in color. In addition to being a replacement for several cadmium yellows, it also serves as a nontoxic visual replacement for the older chromate pigments made with zinc, lead, and strontium. If a green pigment and barium sulfate (for increased transparency) are added, it can also serve as a replacement for barium chromate, which possesses a more greenish cast than the others.
=== Synthesis === Trimebutine can be synthesised from 1-phenylpropan-1-one (1). Firstly, it is converted to the corresponding oxirane through trimethylsulfoxonium idoide with sodium hydride in DMSO and THF, yielding 2-ethyl-2-phenyl-oxirane (2). Next, 2 undergoes ring-opening with dimethylaluminium N,N-dimethylamide in diethyl ether, yielding 2-(dimethylamino)-2-phenyl-butan-1-ol (4) and 2-phenylbutanal (3) as a byproduct. Then, 4 reacts with 3,4,5-trimethoxybenzoyl chloride (5) in triethylamine and THF, which is catalysed by 4-dimethylaminopyrridine (DMAP), yielding trimebutine.
Cuba experienced its lowest-ever temperature of 0 °C (32 °F) on 3 February as measured at a weather station in Matanzas Province. On 4 February, the eastern provinces of Guantánamo, Santiago de Cuba, Holguín and Granma suffered a total blackout, while the western part of the island and Havana suffered serious difficulties with electricity. On 4 March, a shutdown of the Antonio Guiteras Power Plant resulted in power outages for millions of Cubans in the western part of the country. On 16 March, Cuba's power grid collapsed leaving the country without power.
The alkanes from pentane (C5H12) to octane (C8H18) are refined into gasoline, the ones from nonane (C9H20) to hexadecane (C16H34) into diesel fuel, kerosene and jet fuel. Alkanes with more than 16 carbon atoms can be refined into fuel oil and lubricating oil. At the heavier end of the range, paraffin wax is an alkane with approximately 25 carbon atoms, while asphalt has 35 and up, although these are usually cracked in modern refineries into more valuable products. The lightest fraction, the so-called petroleum gases, are subjected to diverse processing depending on cost. These gases are either flared off, sold as liquefied petroleum gas, or used to power the refinery's own burners. During the winter, butane (C4H10) is blended into the gasoline pool at high rates because its high vapour pressure assists with cold starts. The aromatic hydrocarbons are unsaturated hydrocarbons that have one or more benzene rings. They tend to burn with a sooty flame, and many have a sweet aroma. Some are carcinogenic. These different components are separated by fractional distillation at an oil refinery to produce gasoline, jet fuel, kerosene, and other hydrocarbon fractions. The components in an oil sample can be determined by gas chromatography and mass spectrometry. Due to the large number of co-eluted hydrocarbons within oil, many cannot be resolved by traditional gas chromatography. This unresolved complex mixture (UCM) of hydrocarbons is particularly apparent when analysing weathered oils and extracts from tissues of organisms exposed to oil.
Sources: en.wikipedia.org
=== British Isles === A half and half is commonly understood to be a side dish of half chips and half rice. The term is used across the British Isles but most commonly in the north of England and Wales. A typical order might be "chicken curry half and half" or "chili con carne half and half".
The surface tension of liquid ethylene oxide, at the interface with its own vapor, is 35.8 mJ/m2 (0.00079 cal/sq ft) at −50.1 °C (−58.2 °F) and 27.6 mJ/m2 (0.00061 cal/sq ft) at −0.1 °C (31.8 °F). The boiling point increases with the vapor pressure as follows: 57.7 °C (135.9 °F) (2 atm (200 kPa; 29 psi)), 83.6 °C (182.5 °F) (5 atm (510 kPa; 73 psi)), and 114.0 °C (237.2 °F) (10 atm (1,000 kPa; 150 psi)). Viscosity decreases with temperature with the values of 0.577 kPa·s at −49.8 °C (−57.6 °F), 0.488 kPa·s at −38.2 °C (−36.8 °F), 0.394 kPa·s at −21.0 °C (−5.8 °F), and 0.320 kPa·s at 0 °C (32 °F). Between −91 and 10.5 °C (−131.8 and 50.9 °F), vapor pressure p (in mmHg) varies with temperature (T in °C) as
In biochemistry, phosphorylation is described as the "transfer of a phosphate group" from a donor to an acceptor or the addition of a phosphate group to a molecule. A common phosphorylating agent (phosphate donor) is ATP and a common family of acceptor are alcohols:
=== Blood sugar and insulin levels === Erythritol has no effect on blood sugar or blood insulin levels, and therefore may be used as a sugar substitute by people with type 2 diabetes. The glycemic index (GI) of erythritol is 0% of the GI for glucose and the insulin index (II) is 2% of the II for glucose.
Damp (or wet) is defined as the condition of an aggregate in which water is fully permeated the aggregate through the pores in it, and there is free water in excess of the SSD condition on its surfaces which will become part of the mixing water.
Sources: en.wikipedia.org
=== Pathways === Opinions differ about optimal screening and diagnostic measures, partly due to differences in population risks, cost-effectiveness considerations, and lack of an evidence base to support large national screening programs. The most elaborate regimen entails a random blood glucose test during a booking visit, a screening glucose challenge test around 24–28 weeks' gestation, followed by an OGTT if the tests are outside normal limits. If there is a high suspicion, a woman may be tested earlier. In the United States, most obstetricians prefer universal screening with a screening glucose challenge test. In the United Kingdom, obstetric units often rely on risk factors and a random blood glucose test. The American Diabetes Association and the Society of Obstetricians and Gynaecologists of Canada recommend routine screening unless the woman is low risk (this means the woman must be younger than 25 years and have a body mass index less than 27, with no personal, ethnic or family risk factors) The Canadian Diabetes Association and the American College of Obstetricians and Gynecologists recommend universal screening. The U.S. Preventive Services Task Force found there is insufficient evidence to recommend for or against routine screening, and a 2017 a Cochrane review found that there is not evidence to determine which screening method is best for women and their babies.
== Limitations == The BCA assay is largely incompatible with reducing agents and metal chelators, although trace quantities may be tolerated. The BCA assay also reportedly responds to common membrane lipids and phospholipids.
Matt Lenoe described the "revisionist school" as representing those who "insisted that the old image of the Soviet Union as a totalitarian state bent on world domination was oversimplified or just plain wrong. They tended to be interested in social history and to argue that the Communist Party leadership had had to adjust to social forces." These "revisionist school" historians challenged the "totalitarian model", as outlined by political scientist Carl Joachim Friedrich, which stated that the Soviet Union and other communist states were totalitarian systems, with the personality cult, and almost unlimited powers of the "great leader", such as Stalin. It was considered to be outdated by the 1980s and for the post-Stalinist era.
=== Ovarian === AMH is produced by granulosa cells from pre-antral and antral follicles, restricting expression to growing follicles, until they have reached the size and differentiation state at which they are selected for dominance by the action of pituitary FSH. Ovarian AMH expression has been observed as early as 36 weeks' gestation in the humans' fetus. AMH expression is greatest in the recruitment stage of folliculogenesis, in the preantral and small antral follicles. This expression diminishes as follicles develop and enter selection stage, upon which FSH expression increases. Some authorities suggest it is a measure of certain aspects of ovarian function, useful in assessing conditions such as polyendocrine metabolic ovarian syndrome and premature ovarian failure.
It was a serious public-relations problem for Abbott, so the company held interviews and press conferences, at which senior Abbott officials answered questions. The transcripts are archived at [1]. A later study found 3 additional morphs: a metastable polymorph, a trihydrate, and a formamide solvate.
Sources: en.wikipedia.org
It is a complex of the tripeptide glycyl-L-histidyl-L-lysine with a copper(II) ion. The peptide coordinates the metal through its histidine, amino terminus, and an amide nitrogen. It is often listed simply as copper tripeptide-1.
The peptide and its copper form have been detected in human plasma, saliva, and urine. Early reports describe levels that fall with age. The functional meaning of these pools is still debated.
Chromatographic separation gives peptide purity, often reported as a percentage. Copper content is checked by a separate elemental method. Moisture and counter-ions may be reported as well.
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.