A practical reference on glycyl-histidyl-lysine: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-01-05 and is reviewed periodically as new material appears.
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.
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.
Identity and purity are established with a combination of chromatographic and spectroscopic techniques. Reversed-phase high-performance liquid chromatography separates the intact complex from peptide fragments and free copper, and the elution profile yields a purity estimate. Mass spectrometry gives the mass of the intact species and exposes degradation products. Ultraviolet-visible spectroscopy displays a broad absorption band in the visible region that is characteristic of the copper center. Nuclear magnetic resonance is less informative here, because the paramagnetic metal broadens signals and complicates spectral interpretation.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Copper(II) peptide complex | Peptide chain coordinated to a single metal ion |
| CAS number | 89030-95-5 | Indexed for the peptide-copper complex |
| Molecular formula | C14H22CuN6O4 | Approximate formula for a one-to-one complex |
| Appearance | Blue to violet solid | Color from copper d-d transitions |
| Solubility class | Freely soluble in water | Also dispersible in some polar solvents |
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.
The peptide was first isolated from human albumin in 1973 by Loren Pickart, who later described its copper-binding behavior. Early work linked the complex to wound healing and tissue remodeling. Plasma levels of GHK decline with age, a pattern that stimulated interest in topical and supplemental applications. Researchers have reported that the tripeptide influences collagen synthesis, antioxidant defense, and inflammatory signaling in cell and animal models. Human clinical evidence remains limited and often relies on small studies.
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.
Solid GHK-Cu is generally stored as a dry powder under frozen conditions to limit degradation. The peptide bond can hydrolyze, and the copper center can be displaced by strong chelators such as EDTA. Aqueous solutions are less stable than the solid and may lose color or form precipitates over time. Temperature, pH, and oxygen exposure are the main variables that affect shelf life. Neutral to slightly acidic conditions tend to preserve the complex better than strongly alkaline media.
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.
=== November === November 1, 2011 Canada Bick's is closing down its tank farm in Delhi, Ontario in November 2011. One hundred and fifty full-time jobs will be lost by this move in addition to secondary industries and retailers.
=== Variants and subgroups === Regulators and clinical trials often use additional subgroups based on how active the disease is, even if there is no firm agreement on their definition. Examples are 'active MS', 'highly active MS' and 'rapidly evolving severe MS'. One definition of highly active MS is having an unchanged or increased number of relapses even after starting disease-modifying treatment. In addition, the term 'relapsing MS' is often used to denote people with relapsing-remitting MS as well as the subset of individuals with secondary progressive MS who still experience some relapses. The terms "benign MS" is sometimes used for people who have had MS for a long time (15 years or so) with few attacks and little disability. As people may still get worse, the term is discouraged. On the other hand, the term aggressive multiple sclerosis (previously known as "malignant multiple sclerosis") is used to describe people with MS having reached a significant level of disability in a short period. Atypical variants of MS have been described; these include tumefactive multiple sclerosis, Balo concentric sclerosis, and Marburg multiple sclerosis.
As the environments of most organisms are constantly changing, the reactions of metabolism must be finely regulated to maintain a constant set of conditions within cells, a condition called homeostasis. Metabolic regulation also allows organisms to respond to signals and interact actively with their environments. Two closely linked concepts are important for understanding how metabolic pathways are controlled. Firstly, the regulation of an enzyme in a pathway is how its activity is increased and decreased in response to signals. Secondly, the control exerted by this enzyme is the effect that these changes in its activity have on the overall rate of the pathway (the flux through the pathway). For example, an enzyme may show large changes in activity (i.e. it is highly regulated) but if these changes have little effect on the flux of a metabolic pathway, then this enzyme is not involved in the control of the pathway.
Periungual angiofibromas are also termed Koenen's tumors, periungual fibromas, and subungual fibromas. In addition, these tumors were formerly regarded as a type of acral angiofibroma (see below description). These lesions present as multiple nodules or tumors under multiple finger and/or toe nails of individuals with tuberous sclerosis or in one case the Birt-Hogg-Dube syndrome. Periungual angiofibromas have also been reported to occur in individuals that do not have these genetic diseases. Periungual angiofibromas tumors can be highly mutilating finger/toe-nail lesions.
Sources: en.wikipedia.org
== Dosage and imaging == The typical adult dose for a lung imaging study is 40-150 Megabecquerels (1-4 mCi) (containing between 100,000 - 200,000 albumin particles). The particle burden should be lowered for most pediatric patients and lowered to 50,000 for infants. The use of more than 250,000 particles in a dose is controversial as little extra data is acquired from such scans while there is an increased risk of toxicity. Patients with pulmonary hypertension should be administered a minimum number of particles to achieve a lung scan (i.e. 60,000). In any patient by administering a greater quantity of particles than necessary for the diagnostic procedure increases the risks of toxicity. Because of gravity effects, people administered 99mTc MAA should be in the supine position to ensure as even a distribution of particles throughout the lungs as possible. The total percentage of particles trapped in the lungs can be determined through a whole body scan after the administration of 99mTc MAA through the equation:
In October 2023, former Mongolian president Elbegdorj Tsakhia wrote to CNN, expressing his opposition to the death penalty and he cited Singapore as an example. Stating that Mongolia had abolished capital punishment and the crime rate in Mongolia never increased in the aftermath, Elbegdorj stated that he was concerned with the past 16 executions of low to mid-level drug traffickers in Singapore since March 2022, especially the July 2023 hanging of Saridewi Djamani (Singapore's first female to be put to death since 2004), and while he avers his respect for Singapore in terms of its prosperity and stability, Elbegdorj hoped that Singapore could re-evaluate the effectiveness of using the death penalty to curb drug crimes in favour of eventual abolition, due to the death penalty not able to fully uproot the cause of drug trafficking. He also stated that with the newly elected president Tharman Shanmugaratnam taking office, he hoped that the president could affirm the presidential powers of granting clemency to those on death row to soften the government's retentionist stance on capital punishment. In 2024, anti-death penalty activist Kokila Annamalai was the first activist within Singapore to publicly refuse to comply with the Protection from Online Falsehoods and Manipulation Act (POFMA) after the Singaporean government accused her of posting false information about its actions on social media concerning its use of the death penalty.
=== Skin grafts and artificial skin === Two layers of skin created from animal sources as a skin graft is useful in venous leg ulcers. Artificial skin, made of collagen and cultured skin cells, is also used to cover venous ulcers and excrete growth factors to help them heal. A systematic review found that bilayer artificial skin with compression bandaging is useful in the healing of venous ulcers when compared to simple dressings.
Sources: en.wikipedia.org
Charleys Cheesesteaks, officially Charleys Philly Steaks, is an American restaurant chain specializing in Philly cheesesteak headquartered in Columbus, Ohio. Formerly known as Charley's Steakery and Charley's Grilled Subs, the franchise was established in 1986 on the campus of Ohio State University. By 2017 there were 600 locations in 45 states and in 19 countries. Charleys is believed to have doubled in size in 2021. In addition to traditional Philly cheesesteaks, the chain also has other steak based sandwiches and multiple grilled chicken sandwiches, among other grilled sandwiches.
== Applications == Bacterial surface display can be used for a variety of applications. These include affinity-based screening, antibody epitope mapping, the identification of peptide substrates, the identification of cell-binding peptides and vaccine generation.
== In other species == There is much controversy as to the effects of various artemisinin derivatives on α-cell-to-β-cell differentiation in rodents and zebrafish. Li et al., 2017 find artemisinin itself forces α⇨β conversion in rodents (via gephyrin) and zebrafish while Ackermann et al., 2018 find artesunate does not and van der Meulen et al., 2018 find the same absence of effect for artemether (although artemether does inhibit ARX). (Shin et al., 2019 further finds no such effect for GABA in rhesus macaque, although GABA is not an artemisinin but has a related action.) Both Eizirik & Gurzov 2018 and Yi et al., 2020 consider it possible that these are all legitimately varying results from varying combinations of substance, subject, and environment. On the other hand, a large number of reviewers are uncertain whether these are separate effects, instead questioning the validity of Li on the basis of Ackermann and van der Meulen – perhaps GABA receptor agonists as a whole are not β-cell-ergic. Coppieters et al., 2020 goes further, highlighting Ackermann and van der Meulen as publications that catch an unreplicatable scientific result, Li.
Sources: en.wikipedia.org
It is the copper complex of the tripeptide glycyl-L-histidyl-lysine. The metal ion is held by the histidine imidazole group and the peptide N-terminus. Most research on it concerns skin and wound models.
The tripeptide was first isolated from human plasma and has also been reported in saliva and urine. Plasma levels appear to decline with age in some small studies. Those observations rest on limited sample sizes.
It is not authorized as a systemic medicine in most countries. Cosmetic preparations list it as an ingredient rather than an active pharmaceutical substance. Legal status therefore differs by jurisdiction.
Lyophilized material is normally held at about minus twenty degrees Celsius in a sealed, desiccated vial. Dissolved samples are less durable and are prepared fresh. Repeated freeze-thaw cycles are avoided.