If you have been reading about chelation 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 2026-03-12. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Published work on GHK-Cu is dominated by in vitro experiments and small animal studies. Human trials tend to be short and small, with endpoints such as skin appearance rather than clinical outcomes. Review articles often summarize the same underlying laboratory findings, which can make the evidence base look broader than it is. Several basic questions remain open: the concentration of the intact complex in human tissue, the route by which it crosses the skin barrier, and whether effects seen in culture produce measurable changes in people.
Laboratory studies describe GHK-Cu as a source of copper that cells can take up, with reported effects on collagen, elastin, and glycosaminoglycan synthesis in cultured fibroblasts. The peptide also appears in wound-repair research, where it is linked to the activity of matrix metalloproteinases and their inhibitors. These observations come largely from cell and animal models. How directly the complex controls any single pathway in intact human skin remains an open question, and reported effects depend on concentration, vehicle, and exposure time.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Gly-His-Lys | Tripeptide; copper binds via His and N-terminus |
| Copper stoichiometry | Typically 1 Cu(II) per peptide | Can form ternary complexes under some conditions |
| Molecular formula (peptide) | C14H24N6O4 | Free peptide; copper complex mass differs |
| Appearance (solid) | Blue to blue-green powder | Color derives from copper d-d transitions |
| Solubility | Soluble in water and polar solvents | Solubility depends on pH and counterions |
Solid material is typically kept as a lyophilised powder in a sealed, light-protected container at minus 20 degrees Celsius, with desiccant where humidity is high. Working solutions are often prepared fresh, aliquoted and frozen to avoid repeated freeze-thaw cycles. Glassware and buffers are checked for trace metal contamination, since other transition metals can displace copper. Records of lot number, reconstitution date and storage temperature help trace unexpected colour changes. Blue colour itself is not a reliable purity test, because partly degraded solutions can remain visibly coloured.
Identity and purity are normally checked by reversed-phase high-performance liquid chromatography, often coupled to mass spectrometry. The peptide absorbs in the ultraviolet region, and the copper complex also shows a broad visible absorption band that can be followed spectroscopically. Copper content is measured separately, for example by inductively coupled plasma mass spectrometry or atomic absorption spectroscopy, because the peptide assay alone does not confirm how much metal is bound. Purity figures therefore need a stated basis: peptide peak area, copper content, or both.
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.
Routine handling calls for minimizing freeze-thaw cycles and preparing solutions shortly before use. Glass or inert plastic containers reduce adsorption and metal leaching. Working stocks are often kept at 2–8 °C for short periods, while long-term reference material stays at −20 °C or below. Light protection is prudent because prolonged exposure may accelerate oxidation of the peptide. Documentation of lot number, concentration, and preparation date supports reproducibility in laboratory work.
Analytical verification typically combines reversed-phase high-performance liquid chromatography with ultraviolet-visible detection. The copper complex absorbs visible light near 600–630 nm, giving a characteristic blue signal. Mass spectrometry confirms molecular mass and can detect free peptide or mismatched copper stoichiometry. Copper content is often measured independently by inductively coupled plasma mass spectrometry or atomic absorption spectroscopy. Purity, counterion identity, and residual solvents are additional quality-control parameters that methods may address.
Solid GHK-Cu appears as a blue to blue-violet powder, and the colour is a direct consequence of copper coordination. The complex dissolves readily in water and in many polar solvents, while the free peptide behaves differently. Solubility in nonpolar media is low, which limits its use in oil-based systems. Solutions are typically prepared fresh because the dissolved form is more exposed to hydrolysis and to loss of the metal ion than the dry powder. Working concentrations are usually low, and preparation notes often specify the solvent and the order of addition.
Dry material is typically held at low temperature, often around minus twenty degrees Celsius, and protected from moisture and light. Copper complexes can release their metal ion under acidic conditions or in the presence of competing chelators. Hydrolysis of the peptide backbone is a slower but real pathway, and the histidine residue is susceptible to oxidation over long periods. Stability statements therefore depend on formulation, pH, and container, and they should be read as conditional rather than absolute.
The multiaxial diagnostic system of previous editions has been eliminated with the introduction of the DSM-5, with all disorders, including personality disorders, being integrated into Section II of the manual. For a diagnosis of BPD, an individual must meet five out of nine specified diagnostic criteria. The DSM-5 characterizes BPD as a pervasive pattern of instability in interpersonal relationships, self-image, affect, and a significant propensity towards impulsive behavior. Marsha Linehan highlights the diagnostic challenges faced by mental health professionals in using the DSM criteria due to the broad range of behaviors they encompass. To mitigate these challenges, Linehan categorizes BPD symptoms into five principal areas of dysregulation: emotions, behavior, interpersonal relationships, sense of self, and cognition. Moreover, the Alternative DSM-5 Model for Personality Disorders (AMPD), located in Section III of the DSM-5, defines six specific personality disorders—one of them being BPD—in terms of a description of the disorder; the characteristic manner in which the disorder impacts personality functioning, i.e. identity, self-direction, empathy and intimacy (criterion A); as well as a listing and description of the pathological personality traits associated with the disorder (criterion B).
=== Celtic Biotech Iowa, Inc. === Celtic Biotech Iowa's subsidiary, Celtic Biotech LTD, was founded in Dublin, Ireland in 2003 by brothers John Reid and Dr. Paul Reid (the latter of whom serves as the president of Celtic Biotech). Celtic Biotech made headlines in 2011 when they announced a clinical trial to test the effectiveness of Crotoxin, a protein found in South American rattlesnake venom, that could cause cell death in malignant cancer cells. Crotoxin was tested on patients in the George Pompidou University Hospital in Paris. In 2014, Celtic Biotech LTD entered into a share exchange agreement with Spotlight Innovation's wholly owned subsidiary, Celtic Biotech Iowa, Inc. Celtic Biotech LTD also became a subsidiary of Celtic Biotech Iowa. Since then, Celtic Biotech Iowa has produced the commercial product, EPISORB, a topical gel formulated to deliver drugs transdermally. The company also licensed a cardiotoxin therapy for acute and chronic nephropathy in 2015. In January, 2015, Celtic Biotech Iowa was granted a patent by the U.S. Patent and Trademark Office entitled Crotoxin Administration for Cancer Treatment and Pain Relief. In July 2015, the company entered into a research agreement with Atlanta-based Emory University to study the viability of the cell-penetrating peptide Crotamine—a protein found in the venom of the South American rattlesnake, crotalus durissus terrificus—as a radiopharmaceutical for imaging lung cancer tumors with Positron Emission Tomography (PET). In Sept.
Henry Drysdale Dakin FRS (12 March 1880 – 10 February 1952) was an English chemist. He was born in London as the youngest of 8 children to a family of steel merchants from Leeds. As a school boy, he conducted water analysis with the Leeds City Analyst. He was taught chemistry by Julius B. Cohen at the University of Leeds, and then he worked with Albrecht Kossel on arginase at the University of Heidelberg. He joined Columbia University in 1905, working in the lab of Christian Herter. During his work on amino acids he obtained his PhD from Leeds. In 1905, he was one of the first scientists to successfully synthesise adrenaline in the laboratory (see: History of catecholamine research). In 1914 he went back to England to offer his service with the war effort. Due to a request for a chemist by Alexis Carrel to the Rockefeller Institute, Dakin joined Carrel in 1916 at a temporary hospital in Compiègne. There they developed the Carrel–Dakin method of wound treatments. This consisted of intermittently irrigating the wound with Dakin's solution, a dilute solution of sodium hypochlorite (the active ingredient in common liquid bleach products) and boric acid. In the process, he analyzed more than 200 candidate substances, and developed quantitative methods to evaluate their effectiveness for disinfection and wound healing. The solution is still widely used for that purpose, as of 2013. The World War I era Rockefeller War Demonstration Hospital (United States Army Auxiliary Hospital No. 1) was created, in part, to promote the Carrel–Dakin method:
12 November – Downing Street confirms that Sue Gray will not take up a role as the prime minister's envoy to the nations and regions. The government sends a contingency of 470 delegates to the COP29 climate summit in Azerbaijan, with an estimated carbon dioxide footprint of at least 338 tons. The delegation is reported to comprise 354 government officials or ministers and 116 others including representatives from British overseas territories and crown dependencies, journalists, business figures and policy experts. By comparison, Italy sends 437, the US 405 and France 115. Starmer tells the COP29 climate conference that the UK will aim to reduce its emissions by 8% by 2035. Stephen Flynn, the SNP's leader at Westminster, announces his intention to stand at the 2026 Scottish Parliament election. Former Welsh government legal advisor Mick Antoniw and ex-minister Julie Morgan tell BBC News that subject to being passed at Westminster, the Terminally Ill Adults (End of Life) Bill would require a vote in the Senedd to become legal in Wales. 13 November – Health Secretary Wes Streeting orders a review into the potential cost to the NHS of implementing changes to the law regarding assisted dying. A report published by the Electoral Commission reveals that over half the 2024 general election candidates faced some kind of abuse. 14 November – Chancellor Rachel Reeves is reported to be planning the "biggest pension reform in decades" by merging council pension schemes into "pension megafunds" hoping they will boost economic growth.
Yonath was accepted to Tichon Hadash high school since her mother could not pay the tuition, she traded her time teaching math lessons to students, which helped pay for her schooling. At a young age, she said, she was inspired by the scientist Marie Curie. However, she stressed that Curie, whom she as a child was fascinated by after reading her biography, was not her "role model". She returned to Jerusalem for college, graduating from the Hebrew University of Jerusalem with a bachelor's degree in chemistry in 1962, and a master's degree in biochemistry in 1964. In 1968, she obtained her PhD from the Weizmann Institute of Science for X-ray crystallographic studies on the structure of collagen, with Wolfie Traub as her PhD advisor. Yonath accepted postdoctoral positions at Carnegie Mellon University (1969) and MIT (1970). While a postdoctoral researcher at MIT she spent some time in the laboratory of subsequent 1976 chemistry Nobel Prize winner William N. Lipscomb, Jr. of Harvard University where she was inspired to pursue very large structures.
Sources: en.wikipedia.org
Cinema Blend called it one of the most underappreciated games of the decade. In 2011, Official Xbox Magazine called it one of the ten PC franchises it wanted on the Xbox 360 console. In 2013, PC Gamer named it one of the 100 Best Horror Games on PC, and PCGamesN called it the seventh-best PC role-playing game. In 2014, Bloodlines was 90th in Empire's readers' poll of the 100 Greatest Video Games of All Time, and Maximum PC chose it as one of the games they wanted to be remastered for contemporary game systems. In 2015, Rock, Paper, Shotgun listed Bloodlines as the PC's 19th Best RPG and 15th Best Horror Game. In 2017, the game was listed 42nd on IGN's list of the Top 100 RPGs of all Time, Den of Geek named it one of the 20 Video Games that Deserve Remakes, and PC Gamer named it one of the best role-playing games of all time. In 2018, USGamer named it the 22nd best RPG of All Time, summarising that "for all of its bugs and questionable gameplay choices... the raw strength of its design still has the power to grab fans." PC Gamer highlighted the haunted "Ocean House Hotel" as a "high point of unexpected horror", comparing it to the Shalebridge Cradle level from Thief: Deadly Shadows (2004) and Ravenholm from Half-Life 2 (2004). In 2020, Rock, Paper, Shotgun named it the 44th-best RPG for PC.
This is further reinforced by a 2020 Cochrane systematic review which did not find enough evidence of reduction of all-cause mortality, serious adverse events, cardiovascular mortality, non-fatal myocardial infarction, non-fatal stroke or end-stage renal disease when comparing metformin monotherapy to sulfonylureas. This same review also did not find improvement in health-related quality of life. In individuals with impaired-glucose tolerance, a 2019 systematic review only found one suitable trial comparing the effects of Sulphonylurea with metformin in reduction or delay of risk of developing type 2 diabetes, however this trial did not report patient-relevant outcomes. Another systematic review completed in the same year suggested that there is limited evidence if the combined use of Metformin with Sulphonylurea compared to the combination of Metformin plus another glucose-lowering intervention, provides benefit or harm in mortality, severe adverse events, macrovascular and microvascular complications. Combined Metformin and Sulphonylurea therapy did appear to lead to higher risk of Hypoglycemia.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH−NH2 group of donors with oxygen as acceptor. The systematic name of this enzyme class is L-amino-acid:oxygen oxidoreductase (deaminating). This enzyme is also called ophio-amino-acid oxidase. As of late 2007, 11 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1F8R, PDB: 1F8S, PDB: 1REO, PDB: 1TDK, PDB: 1TDN, PDB: 1TDO, PDB: 2IID, PDB: 2JAE, PDB: 2JB1, PDB: 2JB2, and PDB: 2JB3.
The Director General functions from the West Bengal Police Directorate, located in the Writers' Buildings, the State Government's main Secretariat in Central Kolkata. He is assisted by a team of senior officers from the ranks of Additional Director General & Inspector General of Police to Assistant Inspector General of Police (AIG — a post equivalent in rank and status to the Superintendent of Police). Officers of the rank of Deputy Superintendent of Police are selected by the West Bengal Public Service Commission through the West Bengal Civil Service (Executive & other services) examinations. In addition to this, the directly recruited Sub Inspectors of Police may also become Deputy Superintendent of Police on promotion. The West Bengal Police maintains the following ranks:
Sources: en.wikipedia.org
and new varieties are being developed continually to improve frost tolerance, disease resistance, machine harvesting, fruit quality, nutritional content and fruit flavour. Varieties producing green fruit, less strongly flavoured and sweeter than typical blackcurrants, are cultivated in Finland, where they are called "greencurrants" (viherherukka). In Poland, the Research Institute of Horticulture has done work on improving the blackcurrant with regard to disease and pest resistance, fruit quality, adaptations to local conditions and mechanical harvesting. Researchers have crossed various varieties and introduced inter-specific genetic material from the gooseberry (Ribes grossularia), the redcurrant (Ribes rubrum) and the flowering currant (Ribes sanguineum). The resulting offspring were further back-crossed to R. nigrum. Cultivars produced include 'Tisel' and 'Tiben' in 2000 and 'Ores', 'Ruben' and 'Tines' in 2005. Further cultivars 'Polares' and 'Tihope' are being tested. Since 1991, New Zealand has become an important centre for research and development, as its temperate climate is particularly suitable for cultivation of the crop. Breeding programmes are concentrating on yield, large fruit size, consistency of cropping and upright habit. In North America, there is a need for this fruit to have resistance to white pine blister rust. New cultivars such as 'Crusader', 'Coronet' and 'Consort' have been developed there by crossing R. nigrum with R. ussuriense and these show resistance to the disease.
According to the lipid hypothesis, elevated levels of cholesterol in the blood lead to atherosclerosis, which may increase the risk of heart attack, stroke, and peripheral artery disease. Since higher blood LDL – especially higher LDL concentrations and smaller LDL particle size – contributes to this process more than the cholesterol content of the HDL particles, LDL particles are often termed "bad cholesterol". High concentrations of functional HDL, which can remove cholesterol from cells and atheromas, offer protection and are commonly referred to as "good cholesterol". These balances are mostly genetically determined but can be changed by body composition, medications, diet, and other factors. A 2007 study demonstrated that blood total cholesterol levels have an exponential effect on cardiovascular and total mortality, with the association more pronounced in younger subjects. Because cardiovascular disease is relatively rare in the younger population, the impact of high cholesterol on health is larger in older people. Elevated levels of the lipoprotein fractions, LDL, IDL and VLDL, rather than the total cholesterol level, correlate with the extent and progress of atherosclerosis. Conversely, the total cholesterol can be within normal limits, yet be made up primarily of small LDL and small HDL particles, under which conditions atheroma growth rates are high.
Non-essential nutrients are substances within foods that can have a significant impact on health. Dietary fiber is not absorbed in the human digestive tract. Soluble fiber is metabolized to butyrate and other short-chain fatty acids by bacteria residing in the large intestine. Soluble fiber is marketed as serving a prebiotic function with claims for promoting "healthy" intestinal bacteria.
== Further reading == Dyck E, Elcock C (2023). Expanding Mindscapes: A Global History of Psychedelics. MIT Press. ISBN 978-0-262-37689-1. Halberstadt AL, Franz X. Vollenweider, David E. Nichols, eds. (2018). Behavioral Neurobiology of Psychedelic Drugs. Vol. 36. Berlin, Heidelberg: Springer. ISBN 978-3-662-55878-2. Jay M (2019). Mescaline: A Global History of the First Psychedelic. New Haven, CT: Yale University Press. doi:10.2307/j.ctvgc61q9. ISBN 978-0-300-25750-2. S2CID 241952235. Letheby C (2021). Philosophy of Psychedelics. Oxford: Oxford University Press. doi:10.1093/med/9780198843122.001.0001. ISBN 978-0-19-884312-2. Richards WA (2016). Sacred Knowledge: Psychedelics and Religious Experiences. New York: Columbia University Press. ISBN 978-0-231-54091-9. Siff S (2015). Acid Hype: American News Media and the Psychedelic Experience. Champaign, Illinois: University of Illinois Press. ISBN 978-0-252-09723-2. Winstock, Ar; Timmerman, C; Davies, E; Maier, Lj; Zhuparris, A; Ferris, Ja; Barratt, Mj; Kuypers, Kpc (2021). Global Drug Survey (GDS) 2020 Psychedelics Key Findings Report.
== In vitro self-assembly == Measuring approximately 7 nm in diameter, microfilaments are the thinnest fibers of the cytoskeleton. They are polymers of actin subunits (globular actin, or G-actin), which as part of the fiber are referred to as filamentous actin, or F-actin. Each microfilament is made up of two helical, interlaced strands of subunits. Much like microtubules, actin filaments are polarized. Electron micrographs have provided evidence of their fast-growing barbed-ends and their slow-growing pointed-end. This polarity has been determined by the pattern created by the binding of myosin S1 fragments: they themselves are subunits of the larger myosin II protein complex. The pointed end is commonly referred to as the minus (−) end and the barbed end is referred to as the plus (+) end. In vitro actin polymerization, starts with the self-association of three G-actin monomers to form a trimer. ATP-bound actin then itself binds the barbed end, and the ATP is subsequently hydrolyzed. ATP hydrolysis occurs with a half time of about 2 seconds, while the half time for the dissociation of the inorganic phosphate is about 6 minutes. This autocatalyzed event reduces the binding strength between neighboring subunits, and thus generally destabilizes the filament. In vivo actin polymerization is catalyzed by a class of filament end-tracking molecular motors known as actoclampins. Evidence suggests that the rate of ATP hydrolysis and the rate of monomer incorporation are strongly coupled.
Sources: en.wikipedia.org
GHK-Cu is a complex of the tripeptide glycyl-L-histidyl-L-lysine with copper(II). The peptide coordinates the metal through its histidine imidazole, terminal amino group, and amide nitrogen. It is studied in biochemistry and dermatological research.
Yes, the peptide and its copper complex have been detected in human plasma, saliva, and urine. Endogenous concentrations are low and vary with physiological state. Its natural functions are not fully established.
Copper binding changes the peptide's charge, shape, and reactivity. The complex can participate in redox chemistry and interact with proteins differently than the free peptide. These differences are why studies specify whether they used GHK or GHK-Cu.
It is not approved as a pharmaceutical in major markets and is used mainly as a cosmetic ingredient and a laboratory reagent. Regulatory status varies by country and by the product category in which it appears. Claims about therapeutic effects should be treated separately from permitted cosmetic labeling.