Everything below concerns lyophilized solid. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-01-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| INCI name | Copper tripeptide-1 | Standard designation on cosmetic ingredient labels |
| Peptide sequence | Gly-His-Lys | Three-residue ligand; binding occurs at the histidine side chain |
| Metal-to-peptide ratio | 1 to 1 | One copper(II) ion per peptide unit |
| Appearance | Blue to violet powder | Colour arises from copper-to-peptide electronic transitions |
| Water solubility | Freely soluble | Commonly formulated in aqueous or water-alcohol systems |
Analytical verification commonly relies on high-performance liquid chromatography for purity assessment and mass spectrometry for identity confirmation. Spectroscopic methods such as UV-visible absorption and electron paramagnetic resonance can probe the metal centre itself, since the d9 configuration of copper(II) produces characteristic signals. Elemental analysis or plasma-based techniques quantify copper content. Because each method reports a different aspect of the same sample, purity figures are most meaningful when the technique and its detection wavelength are stated alongside the value.
Stability of the complex in solution depends on pH, temperature, and the presence of competing ligands. It is generally described as more resistant to breakdown than the metal-free chain, since coordination reduces susceptibility to enzymatic attack. Oxidation and hydrolysis can nevertheless proceed over time in aqueous media. Storage guidance in laboratory settings commonly involves refrigeration, protection from light, and avoidance of strongly alkaline conditions. Published data on long-term behaviour vary considerably and depend on the specific matrix.
Handling practices for the solid material emphasise low temperature and dryness. The lyophilised or powdered form is typically kept at refrigerator or freezer temperatures together with a desiccant. Working solutions are often prepared fresh, because repeated freeze-thaw cycles and extended storage may alter the complex. Glass or inert plastic containers are preferred over materials that could leach metal ions into the preparation. Such practices follow general peptide conventions rather than substance-specific regulations.
Dry material is typically held at low temperature, often around minus twenty degrees Celsius, and protected from moisture and light. Copper complexes can release their metal ion under acidic conditions or in the presence of competing chelators. Hydrolysis of the peptide backbone is a slower but real pathway, and the histidine residue is susceptible to oxidation over long periods. Stability statements therefore depend on formulation, pH, and container, and they should be read as conditional rather than absolute.
Identity and purity are usually assessed with reversed-phase high-performance liquid chromatography, often paired with mass spectrometry. Copper content is measured separately by techniques such as inductively coupled plasma mass spectrometry or atomic absorption. Amino acid analysis confirms the peptide sequence after hydrolysis. Because the metal and the peptide can be quantified independently, a complete certificate of analysis normally reports both values rather than a single purity figure. This separation of measurements is important when comparing suppliers.
Solid GHK-Cu appears as a blue to blue-violet powder, and the colour is a direct consequence of copper coordination. The complex dissolves readily in water and in many polar solvents, while the free peptide behaves differently. Solubility in nonpolar media is low, which limits its use in oil-based systems. Solutions are typically prepared fresh because the dissolved form is more exposed to hydrolysis and to loss of the metal ion than the dry powder. Working concentrations are usually low, and preparation notes often specify the solvent and the order of addition.
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.
Discovery of GHK is generally attributed to work in the 1970s that isolated a plasma factor influencing liver cell behavior. Subsequent studies identified the copper-binding tripeptide and its ability to chelate copper with high affinity. Early reports linked the complex to wound healing and tissue remodeling in animal models. The free peptide and the copper-bound form have different properties, so the two are distinguished in the literature. Whether endogenous GHK-Cu serves a single primary physiological role remains an open question.
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.
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.
Through this method, researchers can more effectively improve the functional properties of proteins to meet specific biotechnology or medical needs. Although this method has high requirements for information and technology and is relatively difficult to implement, with the development of computing technology and bioinformatics, the application prospects of semi-rational design in protein engineering are becoming more and more broad.
== History == Loperamide hydrochloride was first synthesized in 1969 by Paul Janssen from Janssen Pharmaceuticals in Beerse, Belgium, following previous discoveries of diphenoxylate hydrochloride (1956) and fentanyl citrate (1960). The first clinical reports on loperamide were published in 1973 with the inventor being one of the authors. The trial name for it was "R-18553". Loperamide oxide has a different research code: R-58425. The trial against placebo was conducted from December 1972 to February 1974, its results being published in 1977. In 1973, Janssen started to promote loperamide under the brand name Imodium. In December 1976, Imodium got US FDA approval. During the 1980s, Imodium became the best-selling prescription antidiarrheal in the United States. In March 1988, McNeil Pharmaceutical began selling loperamide as an over-the-counter drug under the brand name Imodium A-D. In the 1980s, loperamide also existed in the form of drops (Imodium Drops) and syrup. Initially, it was intended for children's usage, but Johnson & Johnson voluntarily withdrew it from the market in 1990 after 18 cases of paralytic ileus (resulting in six deaths) were registered in Pakistan and reported by the World Health Organization (WHO). In the following years (1990-1991), products containing loperamide have been restricted for children's use in several countries (ranging from two to five years of age). In the 1980s, before the US patent expired on 30 January 1990, McNeil started to develop Imodium Advanced containing loperamide and simethicone for treating both diarrhea and gas.
=== By mouth === An oral preparation exists but is not widely available. The amphipathic nature of amphotericin along with its low solubility and permeability has posed major hurdles for oral administration given its low bioavailability. In the past it had been used for fungal infections of the surface of the GI tract such as thrush, but has been replaced by other antifungals such as nystatin and fluconazole. However, recently novel nanoparticulate drug delivery systems such as AmbiOnp, nanosuspensions, lipid-based drug delivery systems including cochleates, self-emulsifying drug delivery systems, solid lipid nanoparticles and polymeric nanoparticles—such as amphotericin B in pegylated polylactide coglycolide copolymer nanoparticles—have demonstrated potential for oral formulation of amphotericin B. The oral lipid nanocrystal amphotericin by Matinas Biopharma is furthest along, having completed a successful phase 2 clinical trial in cryptococcal meningitis.
The xanthoproteic reaction (xanthoprotic test) is a method that can be used to detect a presence of protein soluble in a solution, using concentrated nitric acid. The test gives a positive result in amino acids carrying aromatic groups, especially in the presence of tyrosine. If the test is positive the proof is neutralized with an alkali, turning dark yellow. The yellow colour is due to xanthoproteic acid which is formed due to nitration of certain amino acids, most common examples being tyrosine and tryptophan. This chemical reaction is a qualitative test, determining the presence or absence of proteins.
A considerable number of those killed during the uprising were killed by protestors in acts of vigilante justice, including in some cases by necklacing, although many others were killed by state security forces or by rival vigilantes. Opposition to black local authorities constituted an intersection between local and socioeconomic grievances, on the one hand, and broad opposition to apartheid, on the other. Many of the civic and student organisations which drove the protests – among them the Congress of South African Students – were formally or informally aligned to the United Democratic Front (UDF), which in turn was aligned to the exiled African National Congress (ANC). Although there remains debate about the extent to which the UDF and ANC provided the organisational and strategic impetus for the uprising, their anti-apartheid ideology and symbols were given prominent place. The government met the uprising with severity, deploying the South African Defence Force to police the townships from October 1984. A partial state of emergency was enforced in the Transvaal and Cape Province from July 1985, extended in October 1985, and then surpassed in June 1986 by a stronger state of emergency, which applied across the country and remained in place for four years thereafter. The national state of emergency is viewed as having dampened the uprising by the end of 1986, but continuous protest and intermittent violence remained a feature of township life until negotiations to end apartheid were completed in 1994.
Sources: en.wikipedia.org
== 20th Century == 1901: Florence Bascom became the first female geologist to present a paper before the Geological Survey of Washington. 1903: Marie Curie became the first woman to win the Nobel Prize, awarded in Physics, and went on to also win the Nobel Prize in Chemistry. She performed pioneering research in radioactivity, and discovered two elements (polonium and radium). 1912: Henrietta Swan Leavitt studied the bright-dim cycle periods of Cepheid stars, then found a way to calculate the distance from such stars to Earth. 1924: Florence Bascom became the first woman elected to the Council of the Geological Society of America. 1925: Florence Sabin became the first woman elected to the National Academy of Sciences. 1928: Alice Evans became the first woman elected president of the Society of American Bacteriologists. 1936: Edith Patch became the first female president of the Entomological Society of America.
In Situ and Ex Situ NMR Techniques NMR technology can be divided into two main experimental approaches in battery research: In Situ NMR and Ex Situ NMR. Each offers unique advantages depending on the research goals.
Laserspray inlet ionization (LSII) is a subset of MAII and uses a matrix-assisted laser desorption/ionization (MALDI) method. It was originally called atmospheric pressure matrix-assisted laser desorption/ionization however was renamed as LSII to avoid confusion with MALDI and as it was found to be a type of inlet ionization. As all inlet ionization techniques, highly multiply charged ions are produced. A nitrogen laser is used to ablate the solid matrix/analyte into the heated inlet tube, the observed ions are generated at the surface of the matrix/analyte and so the laser is not directly involved in the ionization as was originally thought. LSII can determine protein molecular weights and has been found to detect masses of proteins up to 20,000 Da. The sensitivity of LSII, for protein detection, is higher by an order of magnitude compared to ESI.
=== Non-nutrients === Ethanol (C2H5OH) is not an essential nutrient, but it does supply approximately 29 kilojoules (7 kilocalories) of food energy per gram. For spirits (vodka, gin, rum, etc.) a standard serving in the United States is 44 millilitres (1+1⁄2 US fluid ounces), which at 40% ethanol (80 proof) would be 14 grams and 410 kJ (98 kcal). At 50% alcohol, this would be 17.5 g and 513 kJ (122.5 kcal). Wine and beer contain a similar amount of ethanol in servings of 150 and 350 mL (5 and 12 US fl oz), respectively, but these beverages also contribute to food energy intake from components other than ethanol. A 150 mL (5 US fl oz) serving of wine contains 420 to 540 kJ (100 to 130 kcal). A 350 mL (12 US fl oz) serving of beer contains 400 to 840 kJ (95 to 200 kcal). According to the U.S. Department of Agriculture, based on NHANES 2013–2014 surveys, women ages 20 and up consume on average 6.8 grams of alcohol per day and men consume on average 15.5 grams per day. Ignoring the non-alcohol contribution of those beverages, the average ethanol contributions to daily food energy intake are 200 and 450 kJ (48 and 108 kcal), respectively. Alcoholic beverages are considered empty calorie foods because, while providing energy, they contribute no essential nutrients. By definition, phytochemicals include all nutritional and non-nutritional components of edible plants. Included as nutritional constituents are provitamin A carotenoids, whereas those without nutrient status are diverse polyphenols, flavonoids, and lignans that are present in numerous plant foods.
Heseltine played an important role in taking charge of the Millennium Exhibition in Greenwich and ensuring that it happened, even having a meeting with Tony Blair, Leader of the Opposition, in January 1997 to agree that a Labour Government would back it.
Sources: en.wikipedia.org
== Ex vivo or in vivo methods == Methods that screen protein–protein interactions in the living cells. Bimolecular fluorescence complementation (BiFC) is a technique for observing the interactions of proteins. Combining it with other new techniques, dual expression recombinase based (DERB) methods can enable the screening of protein–protein interactions and their modulators. The yeast two-hybrid screen investigates the interaction between artificial fusion proteins inside the nucleus of yeast. This approach can identify the binding partners of a protein without bias. However, the method has a notoriously high false-positive rate, which makes it necessary to verify the identified interactions by co-immunoprecipitation.
=== Physiological effects === According to a dose-response study in human subjects, dimethyltryptamine administered intravenously slightly elevated blood pressure, heart rate, pupil diameter, and rectal temperature, in addition to elevating blood concentrations of beta-endorphin, corticotropin, cortisol, and prolactin; growth hormone blood levels rose equally in response to all doses of DMT, and melatonin levels were unaffected."
To reduce the peptidic nature of ketomethylene inhibitors the P1’ and P2’ substituent may be cyclized to form a lactam, where there is a correlation between the inhibitory potency and the ring size. In 2001 it was postulated that a substitution α to nitrogen and making of 3-methyl-substituted analog of A58365A, a pyridone acid isolated from the fermentation broth of the bacterium Streptomyces chromofuscus with ACE inhibitory activity, might influence the level of biological activity by steric or hydrophobic effect, and/or by preventing reactions at C3. It was also noticed during the synthetic work on A58365A that potential precursors were sensitive to oxidation of the five-membered ring and so the 3-methyl analogue might be more stable in this respect.
== Example compounds == The group of xanthophylls includes (among many other compounds) lutein, zeaxanthin, neoxanthin, violaxanthin, flavoxanthin, and α- and β-cryptoxanthin. The latter compound is the only known xanthophyll to contain a beta-ionone ring, and thus β-cryptoxanthin is the only xanthophyll that is known to possess pro-vitamin A activity for mammals. Even then, it is a vitamin only for plant-eating mammals that possess the enzyme to make retinal from carotenoids that contain beta-ionone (some carnivores lack this enzyme). In species other than mammals, certain xanthophylls may be converted to hydroxylated retinal-analogues that function directly in vision. For example, with the exception of certain flies, most insects use the xanthophyll derived R-isomer of 3-hydroxyretinal for visual activities, which means that β-cryptoxanthin and other xanthophylls (such as lutein and zeaxanthin) may function as forms of visual "vitamin A" for them, while carotenes (such as beta carotene) do not.
Sources: en.wikipedia.org
It is a complex of a three-amino-acid peptide, glycine, histidine and lysine, bound to a single copper(II) ion. The metal is held mainly by the histidine side chain and the peptide backbone. Most commercial material is supplied as an acetate salt rather than as the free complex.
The free peptide was reported in 1973 by Loren Pickart, who isolated it from human plasma. Its copper-binding behaviour was characterised over the following years. The metal-bound form has been the subject of most later research.
Yes. Copper tripeptide-1 is the name used in cosmetic ingredient labelling, while GHK-Cu is the shorthand found in the scientific literature. Both refer to the same peptide-copper complex, and the two terms are interchangeable in most technical documents.
GHK is the free tripeptide, while GHK-Cu includes a bound copper(II) ion. The copper complex is the form most often studied for skin and wound-related activity. The two names are sometimes used interchangeably in product labeling, but they refer to distinct chemical species.