copper tripeptide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-05-16. Numbers and descriptions here follow the published literature rather than marketing material.
GHK-Cu is a coordination complex formed between the peptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The unbound chain, abbreviated GHK, consists of three amino acids and occurs naturally in human plasma, saliva, and urine. Binding of the metal is mediated mainly by the imidazole nitrogen of the histidine residue together with backbone amides, producing a stable chelate. Ingredient nomenclature often lists the same substance as copper tripeptide-1. Its charge and solubility behaviour differ from those of the metal-free chain.
The copper-binding activity of this sequence was described in the 1970s during studies of liver tissue and plasma factors. Early work identified the peptide as a component that influenced copper uptake by cells and that appeared in wound fluid. Later investigations examined its presence across species, reporting the same chain in human and animal samples. A decline in measured concentration with age became a recurring observation, although the underlying causes remain incompletely characterised.
Published studies describe the complex in several research contexts, including collagen synthesis, antioxidant behaviour, and wound repair models. Much of this work is conducted in cultured cells or in small animal systems, and the findings are frequently cited in reviews of copper peptides. Direct clinical evidence in humans is comparatively limited, and reported outcomes vary with formulation and study design. Whether free chain or metal-bound form was used is not always stated, a point that complicates comparison between reports.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Copper(II) peptide complex | Coordination compound rather than a simple salt |
| Peptide sequence | Glycyl-L-histidyl-L-lysine | Abbreviated GHK in most literature |
| Molecular formula | C14H22N6O4Cu | Reported for the 1:1 complex |
| Principal binding site | Histidine imidazole nitrogen | Backbone amides contribute additional coordination |
| Common synonym | Copper tripeptide-1 | Used in ingredient and product labelling |
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.
Identity and purity are usually assessed with reversed-phase high-performance liquid chromatography, often paired with mass spectrometry. Copper content is measured separately by techniques such as inductively coupled plasma mass spectrometry or atomic absorption. Amino acid analysis confirms the peptide sequence after hydrolysis. Because the metal and the peptide can be quantified independently, a complete certificate of analysis normally reports both values rather than a single purity figure. This separation of measurements is important when comparing suppliers.
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.
The peptide portion consists of three amino acids: glycine, histidine and lysine. Copper(II) coordinates through the imidazole nitrogen of histidine, the alpha-amino group of glycine and a deprotonated amide nitrogen of the backbone, producing a roughly square-planar geometry. This arrangement gives the complex its characteristic blue-to-violet colour and helps it resist dissociation in water. Reported stability constants are high, although values differ between studies because of differences in ionic strength and measurement method.
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.
For example, for a sucrose ester mixture containing 80% of sucrose monoester, HLB = 16. This equation has been applied regardless the length of the fatty chain. A correspondence table can be written for different grades of sucrose esters according to this equation. The values calculated correspond quite closely with the data given by the suppliers (the data have been harvested from the respective suppliers' websites in March 2020).
==== Photoresists ==== Photoresists are light-sensitive materials, composed of a polymer, a sensitizer, and a solvent. Each element has a particular function. The polymer changes its structure when it is exposed to radiation. The solvent allows the photoresist to be spun and to form thin layers over the wafer surface. Finally, the sensitizer, or inhibitor, controls the photochemical reaction in the polymer phase. Photoresists can be classified as positive or negative. In positive photoresists, the photochemical reaction that occurs during exposure, weakens the polymer, making it more soluble to the developer so the positive pattern is achieved. Therefore, the masks contains an exact copy of the pattern, which is to remain on the wafer, as a stencil for subsequent processing. In the case of negative photoresists, exposure to light causes the polymerization of the photoresist so the negative resist remains on the surface of the substrate where it is exposed, and the developer solution removes only the unexposed areas. Masks used for negative photoresists contain the inverse or photographic "negative" of the pattern to be transferred. Both negative and positive photoresists have their own advantages. The advantages of negative photoresists are good adhesion to silicon, lower cost, and a shorter processing time. The advantages of positive photoresists are better resolution and thermal stability.
== Overview == Dating analyses in 2016 determined that Denny (Denisova 11) died about 90,000 years ago, and the bone's cortical thickness indicates an age at death of at least 13 years. An analysis of the whole genome sequence (total mitochondrial and nuclear DNA) indicates she was female, with a Neanderthal mother and a Denisovan father. While previous analyses of other ancient genomes concluded that Denisovans, Neanderthals, and modern humans interbred during the ice age in Europe and Asia, this find is the most direct evidence yet that various ancient hominins mated with each other and had offspring. Previous analyses from other fossils found in this Siberian cave have shown that modern humans, Neanderthals, and Denisovans inhabited this site at various times, and that all three human species interbred with each other. The genes of both archaic human species are present in many people today, which suggests that when these groups met, gene flow occurred. It is not evident if the mating was consensual or if Denny was fertile. The discovery of Denisova 11 may support the notion that Neanderthals and Denisovans may not have undergone direct extinction but were partly assimilated into modern human populations.
Sources: en.wikipedia.org
=== Epilepsy === In the United States, the Food and Drug Administration (FDA) has indicated only one brand of prescription cannabidiol, sold under the brand name Epidiolex, for the treatment of seizures associated with Dravet syndrome, Lennox–Gastaut syndrome, or tuberous sclerosis complex in people one year of age and older. While Epidiolex treatment is generally well tolerated, it is associated with minor adverse effects, such as gastrointestinal upset, decreased appetite, lethargy, sleepiness, and poor sleep quality. In the European Union, Epidyolex is indicated for use as adjunctive therapy of seizures associated with Lennox–Gastaut syndrome or Dravet syndrome, in conjunction with clobazam, for people aged two years of age and older. In 2020, the label for Epidiolex in the US was expanded to include seizures associated with tuberous sclerosis complex. Epidiolex/Epidyolex is the first prescription formulation of plant-derived cannabidiol approved by regulatory bodies in the US and Europe.
Hyperthyroidism is one of the most common endocrine conditions affecting older domesticated housecats. In the United States, up to 10% of cats over ten years old have hyperthyroidism. The disease has become significantly more common since the first reports of feline hyperthyroidism in the 1970s. The most common cause of hyperthyroidism in cats is the presence of benign tumors called adenomas. Adenomas cause 98% of cases, but the reason these cats develop such tumors remains under study. The most common presenting symptoms are: rapid weight loss, tachycardia (rapid heart rate), vomiting, diarrhea, increased consumption of fluids (polydipsia), increased appetite (polyphagia), and increased urine production (polyuria). Other symptoms include hyperactivity, possible aggression, an unkempt appearance, and large, thick claws. Heart murmurs and a gallop rhythm can develop due to secondary hypertrophic cardiomyopathy. About 70% of affected cats also have enlarged thyroid glands (goiter). The same three treatments used with humans are also options in treating feline hyperthyroidism (surgery, radioiodine treatment, and anti-thyroid drugs). There is also a special low-iodine diet available that will control symptoms, provided no other food is fed; Hill's y/d formula, when given exclusively, decreases T4 production by limiting the amount of iodine needed for thyroid hormone production. It is the only available commercial diet that focuses on managing feline hyperthyroidism.
The Federal Court of Accounts points to the construction company as the main beneficiary of an alleged cartel scheme of paving companies in Codevasf initiated during the Bolsonaro government. Another controversy involving the name of Juscelino Filho was his omission to the Superior Electoral Court in 2022 of 2.2 million reais in pedigree horses in his campaign declaration for federal deputy. In addition, in the late afternoon of Thursday, 26 January, he used an aircraft of the Brazilian Air Force to depart from Brasília bound for São Paulo on a trip that he justified as urgent. His official commitments lasted 2 hours and 30 minutes, but the trip extended until 30 January. During that weekend, the minister, passionate about horses, devoted himself to an entirely private agenda: he advised buyers of animals, promoted one of his own, participated in pedigree horse auctions, received the "Oscar" of breeders, and inaugurated a square in honor of a horse belonging to his partner.
=== October === 1 October – In a televised address from Downing Street, Prime Minister Sir Keir Starmer condemns Iran's missile attack on Israel and says that Britain "stand[s] with Israel and ... [recognises] her right to self-defence in the face of this aggression". 2 October – Starmer makes his first visit to Brussels as prime minister, where he is attempting to rebuild UK–EU relations. It is reported that Starmer has repaid £6,000 in gifts and hospitality received since becoming prime minister. The Parliamentary Commission on Standards has launched an investigation into Labour peer Lord Alli over allegations of failing to register interests. 3 October – The UK announces that it will give up sovereignty of the Chagos Islands to Mauritius, subject to finalisation of a treaty. BBC presenter Laura Kuenssberg cancels a scheduled televised interview with Boris Johnson after accidentally sending him her briefing notes. Labour MP Kim Leadbeater announces plans to introduce a bill on assisted dying after earlier being selected to put forward a private member's bill. 4 October – GB News loses a High Court challenge against Ofcom in which it hoped to temporarily block the regulator from sanctioning it over its People's Forum programme featuring Rishi Sunak in February, while Sunak was prime minister. GB News is given permission to challenge the ruling, with Ofcom agreeing to hold off publication of its findings until the case is heard.
Sources: en.wikipedia.org
Parafollicular cells, also called C cells, are neuroendocrine cells in the thyroid. They are called C cells because the primary function of these cells is to secrete calcitonin. They are located adjacent to the thyroid follicles and reside in the connective tissue. These cells are large and have a pale stain compared with the follicular cells. In birds and teleost fishes these cells occupy a structure outside the thyroid gland named the ultimopharyngeal body.
=== Dextran-crosslinked microspheres === One application of the glucose polymer dextran in microsphere compositions is as a cross-linker. Dextran and oxidized dextran can be used to crosslink gelatin microspheres to reduce gelatin dissolution, which slows the drug release rate. These dextran/gelatin microspheres can be used to provide slow-release of TRAPP-Br, which is a cancer therapeutic. Hydrogel microspheres synthesized by using porous chitosan polyelectrolyte complex with dextran sulfate as a cross-linker can deliver hydrophobic drugs to the intestines with high efficacy.
== Clinical significance == At birth, the bones of the skull do not meet. If certain bones of the skull grow too fast, then craniosynostosis (premature closure of the sutures) may occur. This can result in skull deformities. If the lambdoid suture closes too soon on one side, the skull will appear twisted and asymmetrical, a condition called "plagiocephaly". Plagiocephaly refers to the shape and not the condition. The condition is craniosynostosis. The lambdoid suture can be damaged by a fall backward.
Sources: en.wikipedia.org
GHK denotes the unbound chain of three amino acids. GHK-Cu describes the form in which a copper(II) ion is held by that chain. The two are not interchangeable in solution, since charge, molecular weight, and reactivity differ.
The chain occurs in human plasma, saliva, and urine. Measured amounts are reported to fall with age. Copper binding by the sequence is treated as part of normal metal handling in tissue.
The bound copper(II) centre contributes to redox behaviour and to stability under physiological conditions. Free copper ions can participate in reactions that generate reactive species, while chelated metal is generally more controlled. The chain may also serve as a carrier for copper in experimental systems.
The letters GHK are the one-letter codes for glycine, histidine and lysine, the three amino acids in the peptide. The suffix Cu indicates that the peptide is bound to a copper ion, normally copper(II).