The short version of GHK-Cu fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-02-13 and is reviewed periodically as new material appears.
Several names circulate for the same material, which complicates literature searches. Cosmetic ingredient lists often use copper tripeptide-1, while older biochemistry papers use glycyl-L-histidyl-lysine or its abbreviation GHK. The copper complex is sometimes written as GHK-Cu(II) to make the oxidation state explicit. Terminology is not fully standardized, so matching a compound across sources requires attention to the exact sequence, the counterion, and the stated copper content. Reviews that compare studies must account for these naming differences before drawing conclusions.
GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine, a short sequence of three amino acids. The peptide was first isolated from human plasma in 1973 during research on factors that influence tissue repair in liver. Its ability to bind copper ions became a central point of interest because the metal changes the peptide's chemistry and its behaviour in laboratory systems. Today the compound appears in cosmetic formulations, cell-culture studies, and biochemistry literature under several names.
The peptide sequence places a histidine in the middle, and this residue dominates metal binding. Copper(II) coordinates through the imidazole nitrogen of histidine and the terminal amino group, forming a stable chelate ring system. Loss of the copper ion leaves the free tripeptide, which has different solubility and reactivity. This structural detail matters because assays that measure only the peptide backbone can miss whether copper is still bound to it.
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 |
|---|---|---|
| Peptide sequence | Gly-His-Lys | Three amino acids, histidine in the middle |
| Complex formula | C14H22CuN6O4 | One copper(II) ion per peptide |
| Molar mass (complex) | approx. 402.9 g/mol | Depends on counterion and hydration state |
| Appearance | Blue to blue-violet solid | Colour arises from copper coordination |
| Common synonyms | Copper tripeptide-1, GHK-Cu | Naming varies between disciplines |
Solutions of GHK-Cu respond strongly to pH, redox conditions, and the presence of competing chelators such as EDTA. Below roughly pH 4 the copper tends to dissociate, because the amide nitrogen donors become protonated and can no longer coordinate. Strongly alkaline conditions instead favour hydrolysis and precipitation of copper hydroxide. Dissolved oxygen and light accelerate breakdown of the peptide backbone, and the copper released during that process can catalyse further oxidation, so dry, cold, dark storage is the usual recommendation.
Routine characterisation relies on reversed-phase high-performance liquid chromatography for peptide purity, paired with mass spectrometry for identity confirmation. Ultraviolet-visible spectroscopy detects the metal centre through its absorption band in the visible region, and inductively coupled plasma mass spectrometry quantifies total copper so that a metal-to-peptide ratio can be calculated. Amino acid analysis confirms the expected residue composition. Together these techniques establish concentration, identity, and stoichiometry, but none of them directly reports biological activity.
Quality specifications for research material commonly state peptide purity, copper stoichiometry, counter-ion identity, and residual water content. Frequent counter-ions include acetate and trifluoroacetate, which differ in mass and in their effect on solubility and handling. Whether batch-to-batch differences in reported responses trace to these parameters or to assay conditions remains an open question, since published comparisons rarely control for all of them at once. Independent verification therefore normally pairs a purity measurement with an elemental copper measurement on the same lot.
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.
==== Antigonadotropic effects ==== CPA has potent antigonadotropic effects via its progestogenic activity. It blunts the gonadotropin releasing hormone (GnRH)-induced secretion of gonadotropins, and accordingly, markedly suppresses circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) at sufficiently high doses. Consequently, levels of progesterone, androstenedione, testosterone, DHT, and estradiol are also markedly lowered at sufficiently high dosages, while an elevation in sex hormone-binding globulin (SHBG) and prolactin levels is observed. The effective dosage of CPA for inhibition of ovulation in women, this being an antigonadotropic effect, is 1 mg/day. CPA alone has been found to suppress ovulation in 3 of 5 women at a dose of 0.5 mg/day and in 5 of 5 women at a dose of 1 mg/day in studies. Ovulation inhibition with 1–2 mg/day CPA in combination with 1–2 mg/day estradiol valerate as a birth control pill (brand name Femilar) occurred in 94.4% of 108 women during the third treatment cycle in one study and in almost 100% of 26 women over 12 treatment cycles in another study (except for one woman who ovulated during her first treatment cycle). Oral CPA has been studied at low dosages of 5 to 20 mg/day as a potential male hormonal contraceptive. A dosage of as low as 5 to 10 mg/day oral CPA has been found to suppress circulating testosterone levels in men by 50 to 70%.
Brine pockets which are accessed by smaller pores can experience a higher abundance of photoautotrophic protists as well as smaller heterotrophic protists due to limited grazing pressure by the reduced abundance of large predators, such as large ciliates and metazoan predators.
=== Dry-cleaning === Supercritical carbon dioxide (SCD) can be used instead of PERC (perchloroethylene) or other undesirable solvents for dry-cleaning. Supercritical carbon dioxide sometimes intercalates into buttons, and, when the SCD is depressurized, the buttons pop, or break apart. Detergents that are soluble in carbon dioxide improve the solvating power of the solvent. CO2-based dry cleaning equipment uses liquid CO2, not supercritical CO2, to avoid damage to the buttons.
Birds excrete their nitrogenous wastes as uric acid in the form of a paste. Although this process is metabolically more expensive, it allows more efficient water retention and it can be stored more easily in the egg. Many avian species, especially seabirds, can also excrete salt via specialized nasal salt glands, the saline solution leaving through nostrils in the beak.
The Southern Rhodesians claimed that Butler justified his refusal to give a written promise by saying that binding Whitehall to a document rather than his word would be against the Commonwealth's "spirit of trust"—an argument that Field eventually accepted. "Let's remember the trust you emphasised", Smith warned, according to Field's account wagging his finger at Butler; "if you break that you will live to regret it." Southern Rhodesia attended the conference, which was held at Victoria Falls over a week starting from 28 June 1963, and among other things it was agreed to formally liquidate the Federation at the end of the year. In the House of Commons afterwards, Butler flatly denied suggestions that he had "oiled the wheels" of Federal dissolution with secret promises to the Southern Rhodesians. Field's government was startled by Britain's announcement in October 1963 that Nyasaland would become fully independent on 6 July 1964. While no date was set for Northern Rhodesian statehood, it was generally surmised that it was going to follow shortly thereafter. Smith was promptly sent to London, where he held a round of inconclusive Southern Rhodesian independence talks with the new British Prime Minister, Sir Alec Douglas-Home.
Sources: en.wikipedia.org
==== Fat repositioning ==== Fat repositioning involves mobilizing orbital fat and redistributing it along the infraorbital rim to improve contour irregularities. This technique is commonly used to smooth the transition between the lower eyelid and cheek and to address tear trough deformities.
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13 November The story of the 1968 My Lai Massacre was revealed to the public by freelance American investigative reporter Seymour Hersh, who was contributing to the Dispatch News Service. The New York Times published a similar report at the same time.
== Related compounds == Other carbamates include methyl carbamate, butyl carbamate, and phenyl carbamate (m. p. 149–152 °C), which can also be prepared from the corresponding chloroformate and ammonia. These esters are white, crystalline solids at room temperature. Except for the phenyl carbamate, they sublime at moderate temperatures; methyl carbamate sublimes at room temperatures. The first two and ethyl carbamate are very soluble in water, benzene, and ether. These other carbamates (methyl, butyl, and phenyl) are only used in small quantities for research purposes.
In the 20-naughts, Gavi had intense internal debate about its role in vaccinations and in health systems strengthening (HSS). This was part of a broader discussion in healthcare about "vertical" approaches (often targeting specific diseases or behaviours) and "horizontal" ones, targeting broad programs such as primary care. At Gavi, some argued that vaccination could not be effectively carried out and sustained without strengthening healthcare, citing experiences in Gavi's vaccination programmes, where availability of staff, training, transport, and funds had hindered vaccination and reporting of vaccination coverage and stocks. There were also worries that Gavi was undermining and paralyzing health care systems. Others argued that HSS was a distraction from Gavi's single-minded focus on vaccines, and HSS was a nebulous concept that could not be defined and quantified. Major donors Norway and Britain supported HSS; USAID and the Bill & Melinda Gates Foundation (and Bill Gates personally) opposed it. The majority of vaccine experts tended to favour technological rather than HSS-based approaches. Pharmaceutical industry representatives were supportive of HSS, possibly because they saw it as key to sustainable markets for their products. In 2005, a narrow vote brought Gavi to endorse an HSS goal. Up to a quarter of Gavi's funding was dedicated to "strengthening the capacity of integrated health systems to deliver immunisation", in practice it has been around 10%. After 2010, this funding went through a joint-venture Health Systems Funding Platform.
Sources: en.wikipedia.org
Derek Thompson of The Atlantic argued that DiCaprio gives his best performances when playing "frauds and cheats and double-crossing liars and mercenaries". Several media publications, such as People, Empire and Harper's Bazaar, have included DiCaprio in their listings of the most attractive actors. In 1998, he sued Playgirl magazine over plans to publish a fully nude picture of him. He has said he does not believe in focusing on appearance—as this is only temporary and can negatively affect one's profession in the industry—and looks for career longevity instead. In 2005, DiCaprio was made a commander of the Ordre des Arts et des Lettres by the French Minister of Culture for his contributions to the arts. In 2016, he was named one of the 100 most influential people in the world by Time magazine. He was included on Forbes' annual list of the world's highest-paid actors in 2008 and from 2010 to 2016 with respective earnings of $45 million, $28 million, $77 million, $37 million, $39 million, $39 million, $29 million and $27 million, topping the list in 2011. The magazine has commended DiCaprio's ability to star in risky, R-rated films that become box office successes. The Hollywood Reporter listed him as one of the 100 most powerful people in entertainment from 2016 to 2019. A writer for the same magazine credits DiCaprio as the rare actor to have a successful career "without ever having made a comic book movie, family film or pre-branded franchise.
=== Historical Use of Insects in Medicine === The medicinal application of insects dates back to ancient civilizations. The Smithsonian Institution has documented historical uses of insects such as the utilization of bee venom therapy in Egyptian medicine for treating arthritis and joint pain. Ancient Greek and Roman physicians, including Galen, recorded the use of insects like cantharidin from blister beetles for dermatological conditions. In medieval Europe powdered insects were included in remedies for various ailments including infections and respiratory disorders.
Helen Mary Heffernan is a New Zealand microbiologist, specialising in antibiotic resistance. In 2020, she was appointed a Companion of the New Zealand Order of Merit, for services to health. The Institute of Environmental Science and Research awarded Heffernan their Lifetime Achievement Award in 2018.
Reproductive Medicine: In 2024, a study demonstrated that SeV-mediated RNA delivery of the Kitl gene successfully re-initiated oogenesis and restored fertility in congenitally and chemotherapy-induced infertile female mice without genomic integration. Oncology: A 2024 study found that SeV provides more robust and consistent gene delivery into human pancreatic cancer cells than adeno-associated virus (AAV) or lentiviral vectors, regardless of tumor subtype. CRISPR-Cas9 Delivery: A next-generation "interferon-silent" and temperature-sensitive (ts) SeV platform was introduced in 2024, achieving over 90% editing efficiency in primary human hematopoietic stem and progenitor cells (HSPCs). In 2025, this ts SeV platform was further applied to deliver CRISPR/Cas9 for precise engineering of the human cytomegalovirus (HCMV) genome, bypassing traditional bacterial artificial chromosome (BAC) constraints and enabling editing in diverse cell types.
Sources: en.wikipedia.org
The peptide is glycyl-L-histidyl-L-lysine, a three-amino-acid sequence commonly abbreviated GHK. It binds a single copper(II) ion under typical laboratory conditions. The free peptide and the copper complex are separate chemical species with different properties.
The sequence was identified in human plasma in 1973. Early work examined its presence in blood and its proposed role in tissue repair. The copper-binding property was characterized afterward and became the focus of much later research.
The tripeptide has been measured in human plasma and other biological fluids. Whether it circulates mainly as the copper complex or as the free peptide remains an open question. Natural concentrations are low and difficult to measure reliably.
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.