Everything below concerns copper(II) centre. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-01-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
Material described in research and cosmetic supply chains is typically a synthetic peptide supplied as a lyophilized powder. Purity is commonly reported through chromatographic separation, often at 95 percent or higher, while copper content is confirmed by separate elemental analysis. Batch variation in color and solubility can reflect residual counter-ions, moisture, or partial oxidation of the peptide. Because the complex is not a single regulatory entity, specifications differ between suppliers and are not standardized internationally.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide binds copper through its histidine imidazole nitrogen, its terminal amino group, and a deprotonated amide nitrogen, creating a stable chelate ring. The resulting complex carries a distinctive blue to blue-violet color, which arises from copper d-d electronic transitions. In the solid state it is usually handled as a powder, while in solution the complex can dissociate and re-form depending on pH and competing ligands. The name copper tripeptide-1 is widely used in ingredient listings.
The tripeptide was first isolated from a human plasma filtrate in 1973 during studies of tissue repair factors. Later work detected the free peptide and its copper complex in saliva, urine, and wound fluid, suggesting a natural role in tissue remodeling. Plasma concentrations reported in early literature decline with age, a pattern often cited in discussions of skin aging. Whether these endogenous levels are directly functional or largely incidental remains an open question. The peptide sequence is conserved across mammalian species.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H24N6O4 | Free tripeptide, without copper |
| Molecular weight | About 340 g/mol | Peptide portion only |
| Appearance | Blue to violet powder | Color from copper coordination |
| Solubility | Soluble in water | pH influences dissolution |
| Common synonyms | Copper tripeptide-1, Cu-GHK | Seen on ingredient labels |
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.
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.
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.
The Institut National de la Recherche Biomédicale (INRB) is the national medical research organization of the Democratic Republic of the Congo. The responsible ministry is the Ministry of Scientific Research and Technology. The National Biomedical Research Institute (INRB) was founded in 1984. It is a 70,000 m² establishment. It has been a collaborating center of the World Health Organization since 2018, headed by Professor Jean-Jacques Muyembe-Tamfum, MD, PhD, and serving as a national biomedical research laboratory for the Ministry of Health of the Democratic Republic of Congo (DRC). It is a multidisciplinary institute which collectively has hundreds of years of experience in the identification, treatment and prevention of diseases in the DRC. Its foundations are the performance of medical and biological analyzes, applied and translational research, surveillance of communicable diseases and the promotion of professional growth and development. The INRB has continuously developed and trained high-quality researchers and produced exceptional results. More recently, it has made concrete efforts in terms of control, prevention, and research in response to the current Ebola epidemic. It has continuously brought it's expertise to the government of the DRC in the areas of disease surveillance, prevention and intervention. In 30 years of existence, the INRB has quickly become recognized worldwide and has played an essential role in tropical health research.
=== Politics === DiCaprio endorsed Democratic candidate Hillary Clinton for the 2016 United States presidential election. In March 2020, DiCaprio attended a fundraiser for Joe Biden at the home of Paramount Pictures executive Sherry Lansing. Prior to the 2020 election, DiCaprio narrated a Netflix documentary series about voting rights, stating, "All of us may have been created equal. But we'll never actually be equal until we all vote. So don't wait." On social media, DiCaprio urged voters to make a plan to cast their ballots and to draw attention to voter suppression and restrictive voter ID laws, citing VoteRiders as a source of information and assistance. In 2023, DiCaprio testified during the trial against Prakazrel Michel, who is being accused of participating in a foreign influence campaign that was aimed at the Obama and Trump administrations. In 2024, DiCaprio formally endorsed Kamala Harris for president due to her policies on climate change mitigation, and criticized her Republican opponent Donald Trump.
==== Role in cancer ==== In 1863, Rudolf Virchow hypothesized that the origin of cancer was at sites of chronic inflammation. As of 2012, chronic inflammation was estimated to contribute to approximately 15% to 25% of human cancers.
== Privacy concerns with direct TPMS == Because each tire transmits a unique identifier, vehicles may be easily tracked using existing sensors along the roadway. This concern could be addressed by encrypting the radio communications from the sensors but such privacy provisions were not stipulated by the NHTSA.
=== Border controls and traffic restrictions === Switzerland temporarily reintroduced controls at the border with France from 10 to 19 June 2026. The Federal Council stated that although the summit would take place in France, Geneva, Lausanne and the wider Lake Geneva region were exposed to security risks connected with the event. In the canton of Geneva, only seven road border crossings with France remained open from 12 to 18 June 2026: Anières, Moillesulaz, Thônex-Vallard, Bardonnex, Perly, Meyrin and Ferney-Voltaire. Crossings through railway stations and Geneva Airport remained authorised, but other crossings, including for cyclists and pedestrians, were restricted. Geneva authorities also warned of disruption to public transport, road traffic, as well as temporary restrictions affecting some public spaces. A priority access sticker system, known as a macaron, was introduced for eligible essential workers and residents. Geneva authorities stated that access to Switzerland remained possible without one, subject to controls and available crossings. Additional traffic restrictions were introduced on the Geneva motorway network, including restrictions on the A1 motorway between Geneva Airport and the Bardonnex customs crossing during the summit period.
Sources: en.wikipedia.org
==== A. The nasal soft tissues ==== Nasal skin – Like the underlying bone-and-cartilage (osseo-cartilaginous) support framework of the nose, the external skin is divided into vertical thirds (anatomic sections); from the glabella (the space between the eyebrows), to the bridge, to the tip, for corrective plastic surgery, the nasal skin is anatomically considered, as the: Upper third section – the skin of the upper nose is thin, subcutaneous fat layer is thicker and relatively distensible (flexible and mobile), but then tapers, adhering tightly to the osseo-cartilaginous framework, and becomes the thinner skin of the dorsal section, the bridge of the nose. Middle third section – the skin overlying the bridge of the nose (mid-dorsal section) is the thinnest, least distensible, nasal skin, because it most adheres to the support framework. Lower third section – the skin of the lower nose and tip is significantly thicker and less mobile due to a higher density of sebaceous glands. This increased thickness can often efface the underlying cartilaginous framework, requiring more aggressive surgical definition in the tip area. The subcutaneous fat layer is very thin. Nasal lining – At the vestibule, the human nose is lined with a mucous membrane of squamous epithelium, which tissue then transitions to become columnar respiratory epithelium, a pseudo-stratified, ciliated (lash-like) tissue with abundant seromucous glands, which maintains the nasal moisture and protects the respiratory tract from bacteriologic infection and foreign objects.
Tryptophan N-monooxygenase (EC 1.14.14.156, tryptophan N-hydroxylase, CYP79B1, CYP79B2, CYP79B3) is an enzyme with systematic name L-tryptophan,NADPH:oxygen oxidoreductase (N-hydroxylating). It catalyses the following overall chemical reaction:
=== Other potential methods === Diverse techniques to identify PPIs have been emerging along with technology progression. These include co-immunoprecipitation, protein microarrays, analytical ultracentrifugation, light scattering, fluorescence spectroscopy, luminescence-based mammalian interactome mapping (LUMIER), resonance-energy transfer systems, mammalian protein–protein interaction trap, electro-switchable biosurfaces, protein–fragment complementation assay, as well as real-time label-free measurements by surface plasmon resonance, and calorimetry.
Elutriation Evaporation Extraction Leaching Liquid–liquid extraction Solid phase extraction Supercritical fluid extraction Subcritical fluid extraction Field flow fractionation Filtration – Mesh, bag and paper filters are used to remove large particulates suspended in fluids (e.g., fly ash) while membrane processes including microfiltration, ultrafiltration, nanofiltration, reverse osmosis, dialysis (biochemistry) utilising synthetic membranes, separates micrometre-sized or smaller species Flocculation, separates a solid from a liquid in a colloid, by use of a flocculant, which promotes the solid clumping into flocs Fractional distillation Fractional freezing Magnetic separation Oil-water separation, gravimetrically separates suspended oil droplets from waste water in oil refineries, petrochemical and chemical plants, natural gas processing plants and similar industries Precipitation Recrystallization Scrubbing, separation of particulates (solids) or gases from a gas stream using liquid. Sedimentation, separates using vocal density pressure differences Gravity separation Sieving Sponge, adhesion of atoms, ions or molecules of gas, liquid, or dissolved solids to a surface Stripping Sublimation Vapor–liquid separation, separates by gravity, based on the Souders–Brown equation Winnowing Zone refining
Sources: en.wikipedia.org
Adriaens, D. and Verraes, W. (1997). Ontogeny of the maxillary barbel muscles in Clarias gariepinus (Siluroidei: Clariidae), with some notes on the palatine-maxillary mechanism. Journal of Zoology (London) 241, 117–133. Bailey, D.M. , Wagner, H.J., Jamieson, A.J., Ross, M.F. and Priede, I.G. (2007) A taste of the deep-sea: The roles of gustatory and tactile searching behaviour in the grenadier fish Coryphaenoides armatus. Deep-Sea Research Part I: Oceanographic Research Papers, 54(1), pp. 99–108. (doi:10.1016/j.dsr.2006.10.005) de Freitas Barros Neto, L., Frigo, R. G., Gavilan, S. A., de Moura, S. A. B., & Lima, S. M. Q. (2020). Barbel development associated to aquatic surface respiration in Triportheus signatus (Characiformes: Triportheidae) from the semiarid Caatinga rivers. Environmental Biology of Fishes, 103(1), 89–98. https://doi.org/10.1007/s10641-019-00935-x Eakin, R. R., Eastman, J. T. and Vacchi, M. (2006). Sexual dimorphism and mental barbel structure in the South Georgia plunderfish Artedidraco mirus (Perciformes : Notothenioidei : Artedidraconidae). Polar Biology 30, 45–52. Fadaee, B., Pourkazemi, M., Tavakoli, M., Joushideh, H., Khoshghalb, M. R. B., Hosseini, M. R. and Abdulhay, H. (2006). Tagging and tracking juvenile sturgeons in shallow waters of the Caspian Sea (less than 10 m depth) using CWT (Coded Wire Tags) and barbel incision. Journal of Applied Ichthyology 22, 160–165. Fox, H. (1999). Barbels and barbel-like tentacular structures in sub-mammalian vertebrates: A review. Hydrobiologia 403, 153–193. Grover-Johnson, N. and Farbman, A. (1976).
Distribution of the Asian citrus psyllid is primarily in tropical and subtropical Asia. It has been reported in all citrus-growing regions in Asia except mainland Japan. The disease has affected crops in China, India, Sri Lanka, Malaysia, Indonesia, Myanmar, the Philippines, Pakistan, Thailand, the Ryukyu Islands, Nepal, Saudi Arabia, and Afghanistan. Areas outside Asia have also reported the disease: Réunion, Mauritius, Brazil, Paraguay, Florida since 2005, and in several municipalities in Mexico since 2009. On 30 March 2012, citrus greening disease was confirmed in a single citrus tree in California. The first report of HLB in Texas occurred on 13 January 2012, from a Valencia sweet orange tree in a commercial orchard in Texas. Prospects are bleak for the ubiquitous backyard citrus orchards of California as residential growers are unlikely to consistently use the pesticides which provide effective control in commercial orchards. The distribution of the African citrus psyllid includes Africa, Madeira, Saudi Arabia, Portugal, and Yemen. This species is sensitive to high temperatures and will not develop at temperatures greater than 25 °C (77 °F). It is a vector of the African strain of huanglongbing (Candidatus Liberibacter africanus), which is sensitive to heat. This strain is reported to occur in Africa, (Burundi, Cameroon, Central African Republic, Comoros, Ethiopia, Kenya, Madagascar, Malawi, Mauritius, Reunion, Rwanda, South Africa, St. Helena [unconfirmed], Swaziland, Tanzania, Zimbabwe), Saudi Arabia, and Yemen. The disease was not reported in the EU as of 2004.
=== Cow's grass === In Ireland, before the 19th century, a "cow's grass" was a measurement used by farmers to indicate the size of their fields. A cow's grass was equal to the amount of land that could produce enough grass to support a cow.
If the target DNA contains an allele complementary to the probe's 3’ base, the target DNA will completely hybridize to the probe, allowing DNA polymerase to extend from the 3’ end of the probe. This is detected by the incorporation of the fluorescently labeled dNTPs onto the end of the probe. If the target DNA does not contain an allele complementary to the probe's 3’ base, the target DNA will produce a mismatch at the 3’ end of the probe and DNA polymerase will not be able to extend from the 3' end of the probe. The benefit of the second approach is that several labeled dNTPs may get incorporated into the growing strand, allowing for increased signal. However, DNA polymerase in some rare cases, can extend from mismatched 3’ probes giving a false positive result. A different approach is used by Sequenom's iPLEX SNP genotyping method, which uses a MassARRAY mass spectrometer. Extension probes are designed in such a way that 40 different SNP assays can be amplified and analyzed in a PCR cocktail. The extension reaction uses ddNTPs as above, but the detection of the SNP allele is dependent on the actual mass of the extension product and not on a fluorescent molecule. This method is for low to medium high throughput, and is not intended for whole genome scanning. The flexibility and specificity of primer extension make it amenable to high throughput analysis. Primer extension probes can be arrayed on slides allowing for many SNPs to be genotyped at once.
=== Other improvements === It is reported that in addition to the protein sequence, secondary structure formation depends on other factors. For example, it is reported that secondary structure tendencies depend also on local environment, solvent accessibility of residues, protein structural class, and even the organism from which the proteins are obtained. Based on such observations, some studies have shown that secondary structure prediction can be improved by addition of information about protein structural class, residue accessible surface area and also contact number information.
Sources: en.wikipedia.org
It is a complex of the tripeptide glycyl-L-histidyl-L-lysine with a copper(II) ion. The peptide coordinates the metal through its histidine, amino terminus, and an amide nitrogen. It is often listed simply as copper tripeptide-1.
The peptide and its copper form have been detected in human plasma, saliva, and urine. Early reports describe levels that fall with age. The functional meaning of these pools is still debated.
Chromatographic separation gives peptide purity, often reported as a percentage. Copper content is checked by a separate elemental method. Moisture and counter-ions may be reported as well.
GHK denotes the unbound chain of three amino acids. GHK-Cu describes the form in which a copper(II) ion is held by that chain. The two are not interchangeable in solution, since charge, molecular weight, and reactivity differ.