skin penetration 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 2025-09-08. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Material described as GHK-Cu appears in several distinct markets, including cosmetic ingredients, laboratory reagents, and consumer products, and the quality expectations attached to each differ. A certificate of analysis generally reports peptide purity by chromatography, copper content, appearance, and residual solvents or counterions. Counterion identity matters, because the complex is usually supplied as an acetate or a similar salt, and the counterion contributes to the measured mass. Independent verification of sequence and metal stoichiometry is advisable when a material is used for quantitative work. Batch-to-batch variation is common and should be documented rather than assumed negligible.
Copper peptide solutions tend to resist degradation better than many free peptides, because the bound metal protects the N-terminus and reduces susceptibility to some peptidases. Backbone hydrolysis, oxidation of the histidine imidazole ring, and photochemical reactions remain the principal degradation routes. Aqueous solutions are generally most stable near neutral to mildly acidic pH, while strongly alkaline conditions accelerate hydrolysis. Light exposure is usually avoided, since both the peptide and the copper center can take part in photochemical processes. Stability data published by suppliers often describe short-term behavior rather than multi-year shelf life.
| 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 |
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.
Mechanistic accounts focus on how the complex delivers copper and how the released peptide interacts with the extracellular matrix. Copper is an essential cofactor for lysyl oxidase and other enzymes involved in collagen and elastin cross-linking, and GHK is one of several peptides able to carry the metal. Reported effects include altered gene expression in fibroblasts and changes in matrix metalloproteinase activity, although many of these findings come from cell culture rather than whole organisms. The relative contribution of the peptide backbone, the copper ion, and downstream copper metabolism is not fully resolved.
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.
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.
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.
Methyldopa, also known as α-methyl-L-DOPA and sold under the brand name Aldomet among others, is a medication used for high blood pressure. It is one of the preferred treatments for high blood pressure in pregnancy. For other types of high blood pressure including very high blood pressure resulting in symptoms other medications are typically preferred. It can be given by mouth or injection into a vein. Onset of effects is around 5 hours and they last about a day. Common side effects include sleepiness. More severe side effects include red blood cell breakdown, liver problems, and allergic reactions. Methyldopa is in the alpha-2 adrenergic receptor agonist family of medication. It works by stimulating the brain to decrease the activity of the sympathetic nervous system. Methyldopa was discovered in 1960. It is on the World Health Organization's List of Essential Medicines.
=== Prenatal and newborn screening === Checking for hemoglobinopathies begins during pregnancy, with a prenatal screening questionnaire which includes, among other things, a consideration of health issues in the child's parents and close relatives. During pregnancy, genetic testing can be done on samples taken of fetal blood, of amniotic fluid, or chorionic villus sampling. A routine heel prick test, in which a small sample of blood is collected a few days after birth, can detect some forms of hemoglobinopathy.
This could, in turn, result in increased free concentrations of such drugs and increased effects and/or side effects, potentially necessitating dosage adjustments. Bicalutamide has specifically been found to displace coumarin anticoagulants like warfarin from their plasma binding proteins (namely albumin) in vitro, potentially resulting in an increased anticoagulant effect. This is supported by reports of prolonged prothrombin time and internal bleeding after the introduction of bicalutamide in patients previously stable on coumarin anticoagulants. Close monitoring of prothrombin time and dosage adjustment as necessary is recommended when bicalutamide is used in combination with these drugs. However, in spite of this, no conclusive evidence of an interaction between bicalutamide and other drugs was found in clinical trials of nearly 3,000 patients.
Protein combining or protein complementing is a process in which individual plant products that by themselves are deficient in one or more essential amino acids are combined with other plant products in order to provide all the essential amino acids for human life. While all individual plant foods provide at least trace amounts of each of the 20 amino acids, they often have an insufficient amount of some of the nine essential amino acids, making protein combining with multiple complementary foods necessary to obtain a diet with "complete protein". Consuming sufficient amounts of all nine essential amino acids is absolutely essential for human life. As all meats contain all amino acids in sufficient quantities, protein combining is only important for those who eat few to no meats in their regular diet. For those on a vegetarian or vegan diet, therefore, eating a variety of foods that each provide sufficient amounts of some of the essential amino acids is usually the only way to receive a full slate of the nine essential amino acids, since very few plant products provide a sufficient amount of all nine. However, in practice, it is so easy to achieve protein combining that most people do not need to consciously aim to reach a diet with complete protein. For instance, rice and beans, a staple combination throughout the world, combine to provide more than enough of all the essential amino acids just between the two of them.
==== Local government finance ==== In 1979 the Conservatives were strongly represented in local government, as a result of the unpopularity of the outgoing Labour government. Four of the five council associations were Conservative-controlled. Heseltine was able to persuade them to rein in their spending by 1% each year. Whereas previously overspending councils had received extra rate support grants from Whitehall, after six months Heseltine announced a list of fourteen overspending councils who were to have their grant cut, most of them inner London councils and only one of them, Hammersmith & Fulham, Conservative controlled. The move appeared blatantly political as many of the other 114 overspenders were Conservative councils. Council leaders who came to appeal to Heseltine were often humiliated by being interrogated about their budget, to demonstrate their lack of detailed knowledge, before the council treasurer was allowed to speak. From 1980 to 1981 relations with local government became increasingly confrontational, as Labour made large gains in local elections, with a new generation of council leaders such as Ken Livingstone in London and David Blunkett in Sheffield seeking to generate employment through their councils. Council spending now began to rise again, largely as a result of increases by the GLC, Merseyside and West Midlands councils; whereas Labour votes tended to be poorer and eligible for rate rebates, the burden of higher spending tended to fall on businesses and middle class homeowners.
Sources: en.wikipedia.org
tau+Proteins at the U.S. National Library of Medicine Medical Subject Headings (MeSH) GeneReviews/NCBI/NIH/UW entry on MAPT-Related Disorders MR scans of variant CJD CSF tau-positive man Overview of all the structural information available in the PDB for UniProt: P10636 (Microtubule-associated protein tau) at the PDBe-KB.
Familial: Family history of hirsutism with normal androgen levels. Drug-induced: medications were used before the onset of hirsutism. The recommendation is to stop the medication and replace it with another. Minoxidil Androgens like testosterone, anabolic steroids, and androgenic progestins Valproic acid and methyldopa Pregnancy: Due to changes in hormone production Idiopathic: When no other cause can be attributed to an individual's hirsutism, the cause is considered idiopathic by exclusion. In these cases, menstrual cycles and levels of conventionally tested androgens (testosterone, androstenedione, and dehydroepiandrosterone sulfate) are normal. Around 10 to 15% of women with hirsutism have idiopathic hirsutism. Idiopathic hirsutism may be due to increased production of dihydrotestosterone (DHT) in hair follicles and hence may actually still be due to hyperandrogenism. It may be detectable by measurement of DHT or DHT metabolites. Rice et al. 2016 propose that idiopathic hirsutism is caused by epigenetic inheritance of discordant epigenetic markers. It is testable with current technology.
=== Transcriptional modulation === Both human prohibitins have also been suggested to be localized in the cell nucleus and modulate transcriptional activity by interacting with various transcription factors, including nuclear receptors, either directly or indirectly. However, little evidence for nuclear targeting and transcription factor-binding of prohibitins has been found in other organism (yeast, plants, C. elegans, etc.), indicating that this may be a specific function in mammalian cells.
In dental anatomy, the gingival sulcus is an area of potential space between a tooth and the surrounding gingival tissue and is lined by sulcular epithelium. The depth of the sulcus (Latin for groove) is bounded by two entities: apically by the gingival fibers of the connective tissue attachment and coronally by the free gingival margin. A healthy sulcular depth is three millimeters or less, which is readily self-cleansable with a properly used toothbrush or the supplemental use of other oral hygiene aids.
Sources: en.wikipedia.org
Sidibé Aminata Diallo – Malian Academic and politician. former Minister of Basic Education, Literacy, and the National Languages. Mali Diarra Mariam Flantié Diallo - Minister of Communications And Technology, Mali. Souleymane Sidibé (politician) - former Minister of Internal Security and Civil Protection, Foreign Affairs. Ousmane Sy - Politician. former Minister of Territorial Administration and Local Communities; Mali. Sy Kadiatou Sow– Politician and Women's Rights Activist, former governor of Bamako district, the first woman to hold the position in Mali, former minister of foreign affairs, Foreign Malians and African Integration and former Minister of Urban Planning and Habitat. Mali Sangaré Niamoto Ba- Politician, former Ministry of Industry, Investment and Commerce Djibril Sidibé - Malian football player (Born 1982) Djibril Sidibé - French football player of Malian descent (Born 1992) Inna Modja - Singer, songwriter and activist Mamadou Sidibé - Malian musician Moussa Diaby Moctar Ouane- diplomat and politician. Prime minister; former minister of foreign affairs; former ambassador to the United Nations.
the identification of the organism is not sufficient (one desires to go beyond discovery to produce data for genomic characterization), a coinfection is suspected, other simpler assays are ineffective or will take an inordinate amount of time, screening of environmental samples for previously undescribed or divergent pathogens.
== Diversity-oriented libraries == Even though combinatorial chemistry has been an essential part of early drug discovery for more than two decades, so far only one de novo combinatorial chemistry-synthesized chemical has been approved for clinical use by FDA (sorafenib, a multikinase inhibitor indicated for advanced renal cancer). The analysis of the poor success rate of the approach has been suggested to connect with the rather limited chemical space covered by products of combinatorial chemistry. When comparing the properties of compounds in combinatorial chemistry libraries to those of approved drugs and natural products, Feher and Schmidt noted that combinatorial chemistry libraries suffer particularly from the lack of chirality, as well as structure rigidity, both of which are widely regarded as drug-like properties. Even though natural product drug discovery has not probably been the most fashionable trend in the pharmaceutical industry in recent times, a large proportion of new chemical entities still are nature-derived compounds, and thus, it has been suggested that effectiveness of combinatorial chemistry could be improved by enhancing the chemical diversity of screening libraries. As chirality and rigidity are the two most important features distinguishing approved drugs and natural products from compounds in combinatorial chemistry libraries, these are the two issues emphasized in so-called diversity oriented libraries, i.e. compound collections that aim at coverage of the chemical space, instead of just huge numbers of compounds.
Diazepam is a medication with a high risk of misuse and can cause drug dependence. Some pharmacologists recommend urgent action by national governments to improve prescribing patterns of benzodiazepines such as diazepam. A single dose of diazepam modulates the dopamine system in similar ways to how morphine and alcohol modulate the dopaminergic pathways. Between 50 and 64% of rats will self-administer diazepam. Diazepam can substitute for the behavioral effects of barbiturates in a primate study. Diazepam has been found as an adulterant in heroin. Diazepam drug misuse can occur either through recreational misuse, where the drug is taken to achieve a high, or when the drug is continued long term against medical advice. Sometimes, it is used by stimulant users to "come down" and sleep and to help control the urge to binge. These users often escalate dosage from 2 to 25 times the therapeutic dose of 5 mg to 10 mg. A large-scale study in the US, conducted by SAMHSA, using data from 2011, determined that benzodiazepines were present in 28.7% of emergency department visits involving nonmedical use of pharmaceuticals. In this regard, benzodiazepines are second only to opiates, the study found in 39.2% of visits. About 29.3% of drug-related suicide attempts involve benzodiazepines, making them the most frequently represented class in drug-related suicide attempts. Males misuse benzodiazepines as commonly as females.
== Medical uses == Dexrazoxane has been used to protect the heart against the cardiotoxic side effects of chemotherapeutic drugs such as anthracyclines, such as daunorubicin or doxorubicin or other chemotherapeutic agents. However, in July 2011 the European Medicines Agency (EMA) released a statement restricting use only in adult patients with cancer who have received > 300 mg/m2 doxorubicin or > 540 mg/m2 epirubicin and general approval for use for cardioprotection. That showed a possibly higher rate of secondary malignancies and acute myelogenous leukemia in pediatric patients treated for different cancers with both dexrazoxane and other chemotherapeutic agents that are associated with secondary malignancies. On 19 July 2017, based on evaluation of the currently available data the European Commission issued an EU-wide legally binding decision to implement the recommendations of the Committee for Medicinal Products for Human Use (CHMP) on dexrazoxane and lifted its 2011-contraindication for primary prevention of anthracycline-induced cardiotoxicity with dexrazoxane in children and adolescents where high doses (≥ 300 mg/m3) of anthracyclines are anticipated. Dexrazoxane was designated by the US FDA as an orphan drug for "prevention of cardiomyopathy for children and adults 0 through 16 years of age treated with anthracyclines". This decision allows virtually all children to receive dexrazoxane starting with the first dose of anthracycline at the discretion of the treating provider.
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.
The solid is typically held cold and dry, and solutions are kept for shorter periods because hydrolysis proceeds in water. Repeated freeze-thaw cycles are usually avoided, since they can degrade both the peptide and the complex. Container material and headspace also affect how long a sample remains unchanged.