plasma peptide 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.
Last reviewed on 2026-03-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
Copper takes part in redox chemistry, and the same property that makes it useful in enzymes can generate reactive oxygen species when the ion is loosely bound. GHK chelates copper through imidazole, amino, and amide nitrogen donors, which reduces the amount of free copper in solution. Whether that chelation is protective, neutral, or harmful in a given tissue is not settled. Laboratory assays report both antioxidant and pro-oxidant behavior, depending on the conditions and the readout used.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Copper binding sites | Imidazole, amino, and amide nitrogens | Form chelate rings with Cu(II) |
| Conditional binding constant | Reported near 10^16 at neutral pH | Value depends on method and medium |
| Visible absorption | Broad band in the blue-violet region | Source of the characteristic color |
| Common analytical methods | LC-MS, HPLC, UV-Vis, ICP-OES | Used for identity and copper content |
| Main degradation routes | Oxidation, photolysis, hydrolysis | Accelerated by light, heat, and pH extremes |
Copper(II) binds the peptide through four nitrogen donors: the terminal amino group, the imidazole nitrogen of histidine, and two deprotonated amide nitrogens of the peptide backbone. This tetradentate arrangement gives a roughly square-planar geometry, the thermodynamically favoured form near neutral pH. Because the amide nitrogens must lose a proton before they can coordinate, complex formation is strongly pH-dependent, and the fully coordinated species dominates only above mildly acidic conditions. Electronic transitions within the copper d orbital set produce the characteristic blue to violet colour in aqueous solution.
Endogenous GHK occurs in blood plasma, saliva, and urine, and reported plasma concentrations decline with age in several studies. Researchers have proposed that the peptide acts as a copper carrier that delivers the metal to cells and to sites of injury. That transport role is a hypothesis supported by binding measurements and tissue-distribution data rather than a settled mechanism, and the peptide is generally described as a minor contributor to total plasma copper transport. Values reported in wound fluid and certain tissue extracts are higher than in circulating plasma.
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 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.
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.
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.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-lysine and a copper(II) ion. The peptide sequence is conventionally written as Gly-His-Lys, abbreviated GHK. Copper binds through the imidazole nitrogen of histidine, the alpha-amino group, and a deprotonated amide nitrogen, producing a square-planar geometry. The complex carries a net positive charge near physiological pH and is intensely blue in aqueous solution. The metal-free peptide is often written simply as GHK, while the copper-bound form is written GHK-Cu.
The compound was first isolated from human plasma by the biochemist Loren Pickart in 1973. Early work identified it as a factor that altered the behavior of cultured liver cells, and later studies linked it to connective tissue and wound-related processes. Reported plasma concentrations fall markedly between roughly age twenty and age sixty, a pattern that generated interest in copper peptide biology. Whether that decline has functional consequences remains an open question, because differences observed across age groups do not by themselves establish causation. Research interest later expanded into cosmetic and tissue-culture settings.
==== Insects ==== Freeze-drying is used extensively to preserve insects for the purposes of consumption. Whole freeze-dried insects are sold as exotic pet food, bird feed, fish bait, and increasingly for human consumption. Powdered freeze-dried insects are used as a protein base in animal feeds, and in some markets, as a nutritional supplement for human use. Farmed insects are generally used for all of the aforementioned purposes versus harvesting wild insects, except in the case of grasshoppers which are often harvested out of field crops.
Phenethylamine (PEA) is an organic compound, natural monoamine alkaloid, and trace amine, which acts as a central nervous system stimulant in humans. In the brain, phenethylamine regulates monoamine neurotransmission by binding to trace amine-associated receptor 1 (TAAR1) and inhibiting vesicular monoamine transporter 2 (VMAT2) in monoamine neurons. To a lesser extent, it also acts as a neurotransmitter in the human central nervous system. In mammals, phenethylamine is produced from the amino acid L-phenylalanine by the enzyme aromatic L-amino acid decarboxylase via enzymatic decarboxylation. In addition to its presence in mammals, phenethylamine is found in many other organisms and foods, such as chocolate, especially after microbial fermentation. Phenethylamine is sold as a dietary supplement for purported mood and weight loss-related therapeutic benefits; however, in orally ingested phenethylamine, a significant amount is metabolized in the small intestine by monoamine oxidase B (MAO-B) and then aldehyde dehydrogenase (ALDH), which converts it to phenylacetic acid. This means that for significant concentrations to reach the brain, the dosage must be higher than for other methods of administration. Some authors have postulated that phenethylamine plays a role in affection without substantiating these claims with any direct evidence.
Nutrients used in cellular respiration include carbohydrates, amino acids and fatty acids. These nutrients are oxidized to produce carbon dioxide and water, and to release chemical energy to drive the organism's metabolism. Photosynthesis and cellular respiration are distinct processes, as they take place through different sequences of chemical reactions and in different cellular compartments (cellular respiration in mitochondria). The general equation for photosynthesis as first proposed by Cornelis van Niel is:
=== Mosaic Viruses === In 1955, Robert Rice and Kaesberg researched why the tobacco mosaic virus breaks apart after preservation via freeze-drying. Although they did not figure out what caused it specifically, their research allowed them to rule out several possibilities. They found that the act of freeze-drying did not cause the virus to break, as freeze-drying did not cause insulin fibrils or flagella to break. In 1956, Kaesberg discovered a new virus shape, the icosahedral shape. After taking electron micrographs of the bromegrass mosaic virus and the yellow turnip mosaic virus under light shadowing and heavy shadowing, respectfully, Kaesberg was able to come up with an icosahedral model of the viruses. This shape became the modern-day symbol for a virus because, after much more research, the icosahedral shape was one of the most commonly found virus shapes. In 1958, Kaesberg and colleagues discovered a mosaic virus found in alfalfa creates three macromolecules after infecting a plant. Only one of the types of particles produced the virus, but all three had a similar bacillus-like shape and size. These particles looked nothing like the known spherical species of the alfalfa mosaic virus, so they discovered a new isolate in their work. In 1964, Paul Kaesberg and a colleague studied the effects of pH changes on the bromegrass mosaic virus. They found that when the environment's pH is higher than 6.7, there is a decrease in the virus’ sedimentation coefficient. The coefficient goes back up if the pH goes below 6.7.
However, the evidence for each of these complications is not equally strong; in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study for example, there was an increased risk for babies to be large but not small for gestational age in women with uncontrolled GDM. In a recent birth cohort study of 5150 deliveries, a research group active at the University of Helsinki and Helsinki University Hospital, Finland demonstrated that the mother's GDM is an independent factor that increases the risk of fetal hypoxia, during labour. The study was published in the Acta Diabetologica in June 2021. Another finding was that GDM increased the susceptibility of the fetus to intrapartum hypoxia, regardless of the size of the fetus. The risk of hypoxia and the resulting risk of poor condition in newborn infants was nearly 7-fold in the fetuses of mothers with GDM compared to the fetuses of non-diabetic mothers. Furthermore, according to the findings, the risk of needing to perform resuscitation on the newborn after birth was 10-fold. Research into complications for GDM is difficult because of the many confounding factors (such as obesity). Labelling a woman as having GDM may in itself increase the risk of having an unnecessary caesarean section. Neonates born to women with consistently high blood sugar levels are also at an increased risk of low blood glucose (hypoglycemia), jaundice, high red blood cell mass (polycythemia), and low blood calcium (hypocalcemia) and magnesium (hypomagnesemia).
Sources: en.wikipedia.org
Menkes disease is a congenital disease that is a cause of copper deficiency. Menkes disease is a hereditary condition caused by a defective gene involved with the metabolism of copper in the body. Menkes disease has a wide variety of symptoms including floppy muscle tone, seizures, abnormally low body temperature, and a peculiar steel color hair that feels very rough. Menkes disease is usually fatal, with the majority of affected children dying within the first ten years of life.
=== Adobe ColdFusion (2018 Release) === Adobe ColdFusion (2018 release), known generically as ColdFusion 2018, was released on July 12, 2018. ColdFusion 2018 was codenamed Aether during prerelease. As of March 2023, Adobe had released 16 updates for ColdFusion 2018. New or improved features available in all editions (Standard, Enterprise, and Developer) include:
=== Use in torture === A heavy dose of castor oil could be used as a humiliating punishment for adults. Colonial officials used it in the British Raj (India) to deal with recalcitrant servants. Belgian military officials prescribed heavy doses of castor oil in the Congo Free State as a punishment for being too sick to work. Castor oil was also a tool of punishment favored by the Falangist and later Francoist Spain during and following the Spanish Civil War. Its use as a form of gendered violence to repress women was especially prominent. This began during the war where Nationalist forces would specifically target Republican-aligned women, both troops and civilians, who lived in Republican-controlled areas. The forced drinking of castor oil occurred alongside sexual assault, rape, torture and murder of these women. Its most notorious use as punishment came in Fascist Italy under Benito Mussolini. It was a favorite tool used by the Blackshirts to intimidate and humiliate their opponents. Political dissidents were force-fed large quantities of castor oil by fascist squads so as to induce bouts of extreme diarrhea. This technique was said to have been originated by Gabriele D'Annunzio or Italo Balbo. This form of torture was potentially deadly, as the administration of the castor oil was often combined with nightstick beatings, especially to the rear, so that the resulting diarrhea would not only lead to dangerous dehydration but also infect the open wounds from the beatings.
However, the restrictive protocol is not an option with some especially vulnerable patients who may require the best possible efforts to rapidly restore tissue oxygenation. Although transfusions of platelets are far less numerous (relative to RBC), platelet storage lesion and resulting efficacy loss is also a concern.
== Public figures with CMT == US country music singer Alan Jackson. Jackson was definitively diagnosed in his early 50s. US actor Julie Newmar. She played the original Catwoman in the 1960s Batman television series. US Paralympic cyclist Anthony Zahn. He won a bronze medal at the 2008 Beijing Paralympic Games. Jamaica and US fashion designer Rachel Scott, who serves as Creative Director of Proenza Schouler. UK cultural and disability studies academic Professor George McKay. His books include Shakin' All Over: Popular Music and Disability (2014). US Paralympic swimmer Jamal Hill, bronze medallist at the Tokyo 2021 Paralympic Games. US actress Isabelle Tate was reported to have died of a rare variant of the disease in 2025. Irish Paralympic cyclist Eoghan Clifford. US filmmaker and playwright Crystal R. Emery. Known for directing the 2010 documentary The Deadliest Disease in America. Australian wheelchair tennis player Jin Woodman (born 2009)
Sources: en.wikipedia.org
Scholae: the personal guard of the Emperor, created by Constantine I to replace the Praetorian Guard; Palatinae: "palace troops" were the highest ranked units, created by Constantine I after he disbanded the Praetorian Guard, it was comprised originally of former guardsmen; Comitatenses: regular field units, some were newly-formed, others were descended from Early-Empire legions; Pseudocomitatenses: these were limitanei units diverted into the field army and often kept there; some Early Empire legions became pseudocomitatenses units. These units usually numbered between 300 and 2,000 soldiers and some of them kept their original numbering schemes. The primary source for the legions of this era is the Notitia Dignitatum, a late 4th-century document containing all the civil and military offices of both halves of the Roman Empire (revised in c. 420 for the Western Empire).
==== Rome ==== Potassium alum was described under the name alumen or salsugoterrae by Pliny, and it is clearly the same as the stypteria (στυπτηρία) described by Dioscorides. However, the name alum and other names applied to this substance — like misy, sory, chalcanthum, and atramentum sutorium — were often applied to other products with vaguely similar properties or uses, such as iron sulfate or "green vitriol".
== Overview == The ribosomal P-site plays a vital role in all phases of translation. Initiation involves recognition of the start codon (AUG) by initiator tRNA in the P-site, elongation involves passage of many elongator tRNAs through the P site, termination involves hydrolysis of the mature polypeptide from tRNA bound to the P-site, and ribosome recycling involves release of deacylated tRNA. Binding a tRNA to the P-site in the presence of mRNA establishes codon-anticodon interaction, and this interaction is important for small subunit ribosome (30S) contacts to the tRNA. The classical two-state model proposes that the ribosome contains two binding sites for tRNA, P-site and A-site. The A-site binds to incoming aminoacyl-tRNA which has the anti-codon for the corresponding codon in the mRNA presented in the A-site. After peptide formation between the C-terminal carbonyl group of the growing polypeptide chain (attached to a P-site bound tRNA) and the amino group of the aminoacyl-tRNA (A-site bound), the polypeptide chain is then attached to the tRNA in the A-site. The deacylated tRNA remains in the P-site and is released once the peptidyl-tRNA is transferred to the P-site. How is the translocation of the peptidyl-tRNA from the A-site to the P-site achieved to complete the cycle? It was proposed that this is done in two steps by the movement of the two ribosomal subunits with respect to each other, with the formation of an intermediate hybrid structure: the A-site of one subunit with the P-site of the other subunit.
=== Committee assignments === As an independent, Sanders maintains an agreement with the Senate Democratic leadership where he votes with the Democrats on all procedural matters unless the Democratic whip, Dick Durbin, agrees that he need not (a request rarely made or granted). In return he was allowed to keep his seniority and received the committee seats that would have been available to him as a Democrat; in 2013–14 he was chairman of the United States Senate Committee on Veterans' Affairs (during the Veterans Health Administration scandal). Sanders became the ranking minority member on the Senate Budget Committee in 2015 and the chair in 2021; he previously chaired the Senate Veterans' Affairs Committee for two years. Since 2017, he has been chair of the Senate Democratic Outreach Committee. He appointed economics professor Stephanie Kelton, a modern monetary theory scholar, as the chief economic adviser for the committee's Democratic minority and presented a report about helping "rebuild the disappearing middle class" that included proposals to raise the minimum wage, boost infrastructure spending, and increase Social Security payments.
A number of factors, including diet, obesity, and exercise, affect the level of deoxycholate in the human colon. When humans were switched from their usual diet to a meat, egg and cheese based diet for five days, deoxycholate in their feces increased by factors of 2 to 10 fold. Rats fed diets with 30% beef tallow (high fat) had almost 2-fold more deoxycholate in their feces than rats fed 5% beef tallow (low fat). In the same study, adding the further dietary elements of curcumin or caffeic acid to the rats' high fat (30% beef tallow) diet reduced the deoxycholate in their feces to levels comparable to levels seen in the rats on a low fat diet. Curcumin is a component of the spice turmeric, and caffeic acid is a component high in some fruits and spices. Caffeic acid is also a digestive break-down product of chlorogenic acid, high in coffee and some fruits and vegetables. In addition to fats, the type or amount of protein in the diet may also affect bile acid levels. Switching from a diet with protein provided by casein to a diet with protein provided by salmon protein hydrolysate led to as much as a 6-fold increase in levels of bile acids in the blood plasma of rats. In humans, adding high protein to a high fat diet raised the level of deoxycholate in the plasma by almost 50%. Obesity has been linked to cancer, and this link is in part through deoxycholate.
Sources: en.wikipedia.org
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.
Reversed-phase high-performance liquid chromatography and mass spectrometry are common for the peptide portion. Copper content is usually determined by inductively coupled plasma techniques or by spectrophotometry. Ultraviolet-visible spectroscopy takes advantage of the visible absorption band of the copper complex.
Light, oxygen, and elevated temperature promote degradation of the peptide, and strongly acidic or alkaline conditions accelerate hydrolysis. The copper complex is generally more resistant to oxidation than the free peptide. Storage in a dry, dark, cold environment limits loss over time.
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.