lyophilised powder raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-09-23 and is reviewed periodically as new material appears.
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.
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.
Aqueous GHK-Cu solutions are less stable than the dry powder. Light, dissolved oxygen and elevated temperature all accelerate loss of the intact complex, and the main observable changes are fading of the blue colour and the appearance of peptide fragments. Acidic conditions protonate the histidine imidazole and weaken copper binding, while strongly alkaline conditions promote hydrolysis of the peptide backbone. Because several degradation routes operate at once, a single shelf-life figure does not describe all storage conditions.
| Property | Value | Notes |
|---|---|---|
| INCI name | Copper tripeptide-1 | Standard designation on cosmetic ingredient labels |
| Peptide sequence | Gly-His-Lys | Three-residue ligand; binding occurs at the histidine side chain |
| Metal-to-peptide ratio | 1 to 1 | One copper(II) ion per peptide unit |
| Appearance | Blue to violet powder | Colour arises from copper-to-peptide electronic transitions |
| Water solubility | Freely soluble | Commonly formulated in aqueous or water-alcohol systems |
Analytical confirmation usually combines a separation method with a copper-specific measurement. Liquid chromatography or mass spectrometry establishes peptide identity and purity, while an elemental measurement quantifies the metal content. A frequent misconception is that any blue solution contains an intact copper peptide complex; color alone does not confirm structure, because free copper salts and degraded mixtures can also appear colored. Literature on efficacy is mixed, with in vitro findings often more dramatic than human evidence, and reviews note small sample sizes and short follow-up. Open questions include optimal concentration, skin penetration, and long-term effects.
Proposed mechanisms for copper peptide activity center on delivery of copper ions to cells and on peptide fragments acting as signaling molecules. Copper is a cofactor for enzymes involved in collagen cross-linking and antioxidant defense, and the peptide may improve its availability at target sites. Separately, the tripeptide and its breakdown products have been reported to influence gene expression in cultured fibroblasts. Much of this evidence comes from laboratory cell cultures and animal models rather than controlled human trials. The relative contribution of the copper ion and the peptide sequence is therefore not fully settled.
Stability depends on temperature, light exposure, moisture, and the presence of oxidizing or reducing agents. Solid material held dry and protected from light is generally more stable than aqueous solutions, which can undergo gradual degradation. Recommended storage in much of the literature is a freezer at around minus twenty degrees Celsius for long-term retention, with working aliquots kept cold and shielded from light. Repeated freeze-thaw cycles and alkaline pH are commonly noted as factors that accelerate loss of the intact complex, though exact degradation rates vary.
Stability of GHK-Cu in solution depends on pH, temperature, buffer composition, and oxygen exposure. The copper center can undergo reduction or dissociation, especially in the presence of strong metal chelators such as EDTA. Aqueous solutions are often prepared fresh or stored frozen to limit degradation. Lyophilized solid is more stable than liquid formulations, but it can absorb moisture and should be kept dry. Light exposure may also affect copper complexes, though the effect is often modest.
Purity assessment typically involves high-performance liquid chromatography for the peptide and atomic spectroscopy for copper content. The ratio of copper to peptide is a key quality parameter; a value near one indicates proper stoichiometry. Impurities can include free peptide, copper salts, and truncated sequences from synthesis. Because the complex is dynamic, sample preparation and mobile-phase conditions can shift the observed species. Reported purity values therefore depend on the analytical method and should be interpreted with that context.
== Biological properties == Ionophores are widely used in cell physiology experiments and biotechnology as these compounds can effectively perturb gradients of ions across biological membranes and thus they can modulate or enhance the role of key ions in the cell. Many ionophores have shown antibacterial and antifungal activities. Some of them also act against insects, pests and parasites. Some ionophores have been introduced into medicinal products for dermatological and veterinary use. A large amount of research has been directed toward investigating novel antiviral, anti-inflammatory, anti-tumor, antioxidant and neuroprotective properties of different ionophores. Chloroquine is an antimalarial and antiamebic drug. It is also used in the management of rheumatoid arthritis and lupus erythematosus. Pyrithione is used as an anti-dandruff agent in medicated shampoos for seborrheic dermatitis. It also serves as an anti-fouling agent in paints to cover and protect surfaces against mildew and algae. Clioquinol and PBT2 are 8-hydroxyquinoline derivatives. Clioquinol has antiprotozoal and topical antifungal properties, however its use as an antiprotozoal agent has widely restricted because of neurotoxic concerns. Clioquinol and PBT2 are currently being studied for neurodegenerative diseases, such as Alzheimer's disease, Huntington's disease and Parkinson's disease. Gramicidin is used in throat lozenges and has been used to treat infected wounds. Epigallocatechin gallate is used in many dietary supplements and has shown slight cholesterol-lowering effects.
The gastrin-releasing peptide receptor (GRPR), now properly known as BB2 is a G protein-coupled receptor whose endogenous ligand is gastrin releasing peptide. In humans it is highly expressed in the pancreas and is also expressed in the stomach, adrenal cortex and brain. Gastrin-releasing peptide (GRP) regulates numerous functions of the gastrointestinal and central nervous systems, including release of gastrointestinal hormones, smooth muscle cell contraction, and epithelial cell proliferation and is a potent mitogen for neoplastic tissues. The effects of GRP are mediated through the gastrin-releasing peptide receptor. This receptor is a glycosylated, 7-transmembrane G-protein coupled receptor that activates the phospholipase C signaling pathway. The receptor is aberrantly expressed in numerous cancers such as those of the lung, colon, and prostate. An individual with autism and multiple exostoses was found to have a balanced translocation between chromosome 8 and an X chromosome breakpoint located within the gastrin-releasing peptide receptor gene. The transcription factor CREB is a regulator of human GRP-R expression in colon cancer. Activation MOR1D‐GRPR heteromers in the spinal cord mediate the common troublesome opioid-induced itch.
After six weeks of indecision, Mahathir was appointed deputy prime minister on 5 March 1976. Several political figures praised his appointment, recognizing his proven ability and experience. The appointment meant that Mahathir was the anointed successor to the prime ministership. In October, Mahathir was appointed to lead a cabinet committee to review the Petroleum Development Act. To address the growing drug problem, Mahathir launched a nationwide anti-drug campaign in 1978 and announced plans to build a large rehabilitation centre on Pisang Island, Johor. He later warned that if the issue was not addressed, drug abuse could lead to the destruction of the nation. Mahathir is regarded as having been a successful Minister of Education and then Minister of Trade and Industry (1978–81). In the latter post, he implemented a "heavy industries policy", establishing a HICOM, a government-controlled corporation, to invest in the long-term development of manufacturing sectors such as an indigenous car industry. He spent much of his time in the ministry promoting Malaysia through overseas visits. Besides this, as UMNO deputy president, he played a key role in coordinating among the ten component parties of the ruling Barisan Nasional coalition. In the 1978 general election, Mahathir served as BN's election director for the state of Perak. In September 1978, Mahathir launched the Central Unit of the Federal Industrial Development Authority, a streamlined "one-stop agency" aimed at simplifying the application process for licences, permits, and facilities.
=== Pests and predators === Liliaceae are subject to a wide variety of diseases and pests, including insects, such as thrips, aphids, beetles and flies. Also fungi, viruses and vertebrate animals such as mice and deer. An important horticultural and garden pest is the scarlet lily beetle (Japanese red lily beetle, Lilioceris lilii) and other Lilioceris species which attack Fritillaria and Lilium. Lilium species may be food plants for the Cosmia trapezina moth. A major pest of Tulips is the fungus, Botrytis tulipae. Both Lilium and Tulipa are susceptible to a group of five viruses of the family Potyviridae, specifically the potyvirus (named for potato virus Y) group, which includes the tulip-breaking virus (TBV) and the lily streak virus (lily mottle virus, LMoV) resulting in 'breaking' of the color of the flowers. The viruses are transmitted by aphids. This breaking effect was of economic importance during the tulip mania of the seventeenth century, because it appeared to be producing new varieties. In modern times tulip breeders have produced varieties that mimic the effect of the virus, without being infected. One of these varieties is known as 'Rembrandt', after the Dutch artist of that name. Contemporary tulip owners commonly had Rembrandt and other artists paint their flowers to preserve them for posterity, hence the 'broken' tulips were known as Rembrandt tulips at that time. Another modern variety is 'Princess Irene'. One of the tulip breaking viruses is also named the Rembrandt tulip-breaking virus (ReTBV).
Sources: en.wikipedia.org
==== Tolerance ==== Several hypotheses are given about how tolerance develops, including opioid receptor phosphorylation (which would change the receptor conformation), functional decoupling of receptors from G-proteins (leading to receptor desensitization), μ-opioid receptor internalization or receptor down-regulation (reducing the number of available receptors for morphine to act on), and upregulation of the cAMP pathway (a counterregulatory mechanism to opioid effects) (For a review of these processes, see Koch and Hollt).
Watson (United States); Salvador Luria (Italy); Alexandre Yersin (Switzerland); Kitasato Shibasaburō (Japan); Jean-Martin Charcot, Claude Bernard, Paul Broca (France); Adolfo Lutz (Brazil); Nikolai Korotkov (Russia); Sir William Osler (Canada); and Harvey Cushing (United States). As science and technology developed, medicine became more reliant upon medications. Throughout history and in Europe right until the late 18th century, not only plant products were used as medicine, but also animal (including human) body parts and fluids. Pharmacology developed in part from herbalism and some drugs are still derived from plants (atropine, ephedrine, warfarin, aspirin, digoxin, vinca alkaloids, taxol, hyoscine, etc.). Vaccines were discovered by Edward Jenner and Louis Pasteur. The first antibiotic was arsphenamine (Salvarsan) discovered by Paul Ehrlich in 1908 after he observed that bacteria took up toxic dyes that human cells did not. The first major class of antibiotics was the sulfa drugs, derived by German chemists originally from azo dyes.
The known active constituent of Salvia divinorum is a trans-neoclerodane diterpenoid known as salvinorin A (chemical formula C23H28O8). This compound is present in the dried plant at about 0.18%. Salvinorin A is not an alkaloid (meaning it does not contain a basic nitrogen), unlike most known opioid receptor ligands. Salvinorin A is the first documented diterpene hallucinogen. Similar to many psychoactive herbs, Salvia divinorum synthesizes and excretes its active constituent (salvinorin A) via trichomes, of the peltate-glandular morphology, located just beneath the cuticle (subcuticular) layer.
An artificial organ is an engineered device that can be extra corporeal or implanted to support impaired or failing organ systems. Bioartificial organs are typically created with the intent to restore critical biological functions like in the replacement of diseased hearts and lungs, or provide drastic quality of life improvements like in the use of engineered skin on burn victims. While some examples of bioartificial organs are still in the research stage of development due to the limitations involved with creating functional organs, others are currently being used in clinical settings experimentally and commercially.
== Types of wood == Wood is divided, according to its botanical origin, into two kinds: softwoods, from coniferous trees, and hardwoods, from broad-leaved trees. Softwoods are lighter and generally simple in structure, whereas hardwoods are harder and more complex. However, in Australia, softwood generally describes rain forest trees, and hardwood describes Sclerophyll species (Eucalyptus spp). Softwoods such as pine are typically much lighter and easier to dry than hardwoods such as fruit tree wood. The density of softwoods ranges from 350 kg/m3 to 700 kg/m3, while hardwoods are 450 kg/m3 to 1250 kg/m3. Once dried, both consist of approximately 12% of moisture (Desch and Dinwoodie, 1996). Because of hardwood's denser and more complex structure, its permeability is much less than that of softwood, making it more difficult to dry. Although there are about a hundred times more species of hardwood trees than softwood trees, the ability to be dried and processed faster and more easily makes softwood the main supply of commercial wood nowadays.
Sources: en.wikipedia.org
A bill of health is a document issued by the consul or the public authorities of the port which a ship sails from, descriptive of the health of the port at the time of the vessel's clearance. A clean bill of health certifies that at the date of its issue no infectious disease was known to exist either in the port or its neighbourhood. A suspected or touched bill of health reports that rumours were in circulation that an infectious disease had appeared but that the rumour had not been confirmed by any known cases. A foul bill of health or the absence of a clean bill of health implies that the place the vessel cleared from was infected with a contagious disease. The two latter cases would render the vessel liable to quarantine. Another category of biosecurity measures adopted by border control organisations is mandatory vaccination. As a result of the prevalence of Yellow Fever across much of the African continent, a significant portion of countries in the region require arriving passengers to present an International Certificate of Vaccination or Prophylaxis (Carte Jaune) certifying that they have received the Yellow Fever vaccine. A variety of other countries require travelers who have visited areas where Yellow Fever is endemic to present a certificate to clear border checkpoints, as a means of preventing the spread of the disease. Before the emergence of COVID-19, Yellow Fever was the primary human disease subject to de facto vaccine passport measures by border control authorities worldwide.
pentose Any monosaccharide containing five carbon atoms. The compounds ribose and deoxyribose are both pentose sugars, which, in the form of cyclic five-membered rings, serve as the central structural components of the ribonucleotides and deoxyribonucleotides that make up RNA and DNA, respectively.
== Co-discovery of insulin == Best moved in 1915 to Toronto, Ontario, where he started studying towards a bachelor of arts degree at University College, University of Toronto. In 1918, he enlisted in the Canadian Army serving with the 2nd Canadian Tank Battalion. After the war, he completed his degree in physiology and biochemistry. As a 22-year-old medical student at the University of Toronto he worked as an assistant to the surgeon Dr. Frederick Banting and contributed to the discovery of the pancreatic hormone insulin, which led to an effective treatment for diabetes. In the spring of 1921, Banting travelled to Toronto to visit John Macleod, professor of physiology at the University of Toronto, and asked Macleod if he could use his laboratory to isolate pancreatic extracts from dogs. Macleod was initially sceptical, but eventually agreed before leaving on holiday for the summer. Before leaving for Scotland he supplied Banting with ten dogs for experiment and two medical students, Charles Best and Edward Clark Noble, as lab assistants. It was reported that Best and Noble flipped a coin to see who would assist Banting during the first period of four weeks. According to Best, however, this was the product of a journalist’s imagination, or "newspaper fiction". Nonetheless, Frederick Banting is known to have mentioned this story when discussing the discovery of insulin.
== See also == 30mm DS30M Mark 2 Automated Small Calibre Gun British automated mount with 30 mm Bushmaster II Bushmaster III 35/50 mm chain gun Bushmaster IV 40 mm chain gun List of crew-served weapons of the U.S. Armed Forces List of weapons of the United States Marine Corps M230 30 mm automatic cannon Mark 38 25 mm Machine Gun System Bushmaster II 30 mm chain gun Oerlikon KBA 25 mm automatic cannon Shipunov 2A42 30mm automatic cannon
Sources: en.wikipedia.org
It is a complex of a three-amino-acid peptide, glycine, histidine and lysine, bound to a single copper(II) ion. The metal is held mainly by the histidine side chain and the peptide backbone. Most commercial material is supplied as an acetate salt rather than as the free complex.
The free peptide was reported in 1973 by Loren Pickart, who isolated it from human plasma. Its copper-binding behaviour was characterised over the following years. The metal-bound form has been the subject of most later research.
Yes. Copper tripeptide-1 is the name used in cosmetic ingredient labelling, while GHK-Cu is the shorthand found in the scientific literature. Both refer to the same peptide-copper complex, and the two terms are interchangeable in most technical documents.
The colour depends on copper held in a specific coordination environment. When the complex dissociates or the peptide is cleaved, that environment changes and the visible absorption weakens.