Everything below concerns chromatographic purity. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-10-16. Numbers and descriptions here follow the published literature rather than marketing material.
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.
The molecular weight and charge of GHK-Cu depend on the pH and the number of coordinated ligands. At neutral pH, the peptide typically binds one copper ion, but ternary complexes with other biomolecules can form. Spectroscopic methods such as electron paramagnetic resonance and circular dichroism are used to study the coordination environment. Reports on the exact geometry vary because the complex is dynamic in solution. Researchers often use synthetic GHK-Cu rather than extracted material to control stoichiometry and purity.
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.
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.
== Criticism == In a 2002 lawsuit against McDonald's, a judge commented that Chicken McNuggets are a "McFrankenstein" creation. The judge identified that rather than being merely chicken fried in a pan, McNuggets included elements not utilized by the home cook, including unusual sounding ingredients such as extracts of rosemary, vitamins (niacin, thiamine mononitrate, riboflavin, and folic acid) all of which are common in enriched flour, and leavening (baking soda, calcium lactate, etc.). The 2004 documentary Super Size Me states that "[o]riginally created from old chickens that can no longer lay eggs, McNuggets are now made from chickens with unusually large breasts. They're stripped from the bone, and ground-up into a sort of 'chicken mash', which is then combined with all sorts of stabilizers and preservatives, pressed into familiar shapes, breaded, deep-fried, freeze-dried, and then shipped to a McDonald's near you." Super Size Me also alleged inclusion of ingredients such as TBHQ, polydimethylsiloxane, and others not used by a typical home cook. This was subsequently restated by CNN. Marion Nestle, a New York University professor and author of What to Eat, says that the ingredients in McNuggets probably pose no health risks. Before August 2016, dimethylpolysiloxane and TBHQ were listed as ingredients in the McNuggets cooking process. According to Lisa McComb, a media relations representative for McDonald's, dimethylpolysiloxane is used as a matter of safety to keep the frying oil from foaming.
Perspiration, also known as sweat, diaphoresis and hidrosis, is the fluid secreted by sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distributed over much of the body and are responsible for secreting the watery, brackish sweat most often triggered by excessive body temperature. Apocrine sweat glands are restricted to the armpits and a few other areas of the body and produce an odorless, oily, opaque secretion which then gains its characteristic odor from bacterial decomposition. In humans, sweating is primarily a means of thermoregulation, which is achieved by the water-rich secretion of the eccrine glands. Maximum sweat rates of an adult can be up to 2–4 litres (0.5–1 US gal) per hour or 10–14 litres (2.5–3.5 US gal) per day, but is less in children prior to puberty. Evaporation of sweat from the skin surface has a cooling effect due to evaporative cooling. Hence, in hot weather, or when the individual's muscles heat up due to exertion, more sweat is produced. Animals with few sweat glands, such as dogs, accomplish similar temperature regulation results by panting, which evaporates water from the moist lining of the oral cavity and pharynx. Although sweating is found in a wide variety of mammals, relatively few (apart from humans, horses, some primates and some bovidae) produce sweat in order to cool down.
Following diagnosis, the extent of the disease should be established regarding the heart, the lungs, and the muscles/bones (musculoskeletal). Metabolic functions should also be assessed, as lipodystrophy can co-occur with EDMD, by measuring levels of sugar, cholesterol, and triglycerides in the blood. Tests useful for heart evaluation include electrocardiography (EKG), echocardiography (echo), cardiac MRI, and electrophysiology studies. Musculoskeletal function can be assessed by a physical therapist or orthopedist. Regardless of the extent of the disease, cardiac and respiratory complications should be monitored. EKG, holter, and echo are recommended yearly, and additional tests can be indicated depending on heart involvement. Pulmonary function tests (PFTs) are recommended every 2–3 years, or yearly in those with respiratory involvement. Although the root cause of EDMD is not currently treatable, its manifestations and complications can be treated. Heart involvement can be addressed with medications (antiarrhythmics, beta-blockers, and ACE inhibitors), pacemakers, defibrillators, and sometimes heart transplantation. Affecting breathing can be addressed with physical therapy and, later in the disease, mechanical ventilation. Contractures and scoliosis can be addressed with orthopedic surgery. Mobility can be improved with physical therapy, occupational therapy, and mechanical aids (canes, orthoses, wheelchairs).
Sieve tube Companion cell Phloem fibre Phloem parenchyma. Phloem is an equally important plant tissue as it is also part of the 'plumbing system' of a plant. Primarily, phloem carries dissolved food substances throughout the plant. This conduction system is composed of sieve-tube member and companion cells, which are without secondary walls. The parent cells of the vascular cambium produce both xylem and phloem. This usually also includes fibers, parenchyma, and ray cells. Sieve tubes are formed from sieve-tube members laid end to end. The end walls, unlike vessel members in xylem, do not have openings. The end walls, however, are full of small pores where cytoplasm extends from cell to cell. These porous connections are called sieve plates. In spite of the fact that their cytoplasm is actively involved in the conduction of food materials, sieve-tube members do not have nuclei at maturity. It is the companion cells that are nestled between sieve-tube members that function in some manner bringing about the conduction of food. Sieve-tube members that are alive contain a polymer called Callose, a carbohydrate polymer, forming the callus pad/callus, the colourless substance that covers the sieve plate. Callose stays in solution as long as the cell contents are under pressure. Phloem transports food and materials in plants upwards and downwards as required.
At moderate to high doses (5–15 g of raw leaves), at which opioid effects generally appear, additional adverse effects include tachycardia (an increased stimulant effect) as well as the opioid side effects of constipation, dizziness, hypotension, dry mouth, and sweating. Long-term use of high doses of kratom may lead to development of tolerance, dependence, and withdrawal symptoms, including loss of appetite, weight loss, decreased libido, insomnia, muscle spasms, muscle and bone pain, increased yawning and/or sneezing, myoclonus, watery eyes, hot flashes, fever, diarrhea, restlessness, anger, and sadness. This may lead to resumption of use. Frequent use of high doses of kratom may cause tremors, anorexia, weight loss, seizures, psychosis and other mental health conditions. Kratom use has a small but statistically significant association with externalizing mental health disorders. Kratom use may worsen existing mental health conditions. In case reports associating kratom use with psychosis, it remains unclear whether kratom use directly caused psychosis or simply unmasked the condition. Serious toxicity is relatively rare and generally appears at high doses or when kratom is used with other substances. Herb–drug interactions may result when kratom is combined with alcohol, sedatives, benzodiazepines, opioids, caffeine, cocaine, yohimbine, or monoamine oxidase inhibitors (MAOIs). Rhabdomyolysis is one of the rare and serious complications of this herb at high dosage.
Sources: en.wikipedia.org
This notation demonstrates that similar to the Michaelis–Menten equation, where the rate of reaction depends on the percent of the enzyme population interacting with substrate, the effect of the inhibitor is a result of the percent of the enzyme population interacting with inhibitor. The only problem with this equation in its present form is that it assumes absolute inhibition of the enzyme with inhibitor binding, when in fact there can be a wide range of effects anywhere from 100% inhibition of substrate turn over to just >0%. To account for this, the equation can be modified to allow for different degrees of inhibition by including a delta Vmax term.
Variation can still be found in textbooks on the composition of group 3, and some argumentation against this format is still published today, but chemists and physicists who have considered the matter largely agree on group 3 containing scandium, yttrium, lutetium, and lawrencium and challenge the counterarguments as being inconsistent.
In 1990, a team of speleologists uncovered eight mummies, dating back to around 1283 AD, during a rescue excavation in the e 'Asi al-Hadath cave in the Qadisha Valley of Lebanon. The well-preserved spontaneous mummies, including an infant named dubbed Yasmine, offer insights into Maronite villagers' lives during the Mamluk era. The grotto's high altitude and dry conditions naturally mummified the bodies. The discovery provides historical context, aligning with documented Mamluk raids in the region. Artifacts, including pottery with inscriptions, manuscripts, and clothing, suggest a Maronite community, and the mummies' burial practices parallel present-day Lebanese customs. The remains were called "Maronite mummies" because the individuals found in the 'Asi-al Hadath cave were believed to be Maronites, an indigenous Christian community in the region. Some of the mummies have been transferred to the National Museum of Beirut.
In 2022, Newsom was elected to a second term, defeating Republican state senator Brian Dahle with 59.2% of the vote. This was a smaller margin of victory than in 2018, and the first time since 2010 that the Democratic gubernatorial nominee did not win at least 60% of the vote.
Sporting leagues in Hong Kong include Hong Kong Premier League, Hong Kong Premiership (rugby union), Hong Kong A1 Division Championship, and the Hong Kong Ice Hockey League. Famous local sporting clubs include Hong Kong Football Club, South China Athletic Association, Kitchee SC, and Hong Kong Eastern. Hong Kong sports have been described as "Club Life". Some clubs have documented their history thoroughly, while others have disappeared along with their past.
Sources: en.wikipedia.org
==== 30th anniversary celebrations ==== Berlin planned a week-long arts festival from 4 to 10 November 2019 and a citywide music festival on 9 November to celebrate the 30th anniversary. On 4 November, outdoor exhibits opened at Alexanderplatz, the Brandenburg Gate, the East Side Gallery, Gethsemane Church, Kurfürstendamm, Schlossplatz, and the former Stasi headquarters in Lichtenberg.
=== Gary === Gary (voiced by Tony Todd) is a Vortigaunt that suffered a brain injury sometime before the game. He is severed from the Vortessence, meaning he is cut off from the hivemind composed of his fellow Vortigaunts and has been "alone in [his] head". He joins Alyx as she rescues her father Eli from being sent to Nova Prospekt and later helps him get back to Russell's laboratory.
It was limited to solid samples; however, liquid sample recently can also be measured in TC/EA-IRMS system by adapting an autosampler for liquids. The drawback of TC/EA is the relatively big sample size (~ mg), which is smaller than offline combustion/reduction but larger than GC/pyrolysis. It cannot separate different compounds as GC/pyrolysis does and thus only the average for the whole sample can be provided, which is also a drawback for some research.
Shortly thereafter another new scandal broke out, known as the "CESID papers", which forced the resignation of the vice president of the Narcís Serra government and the Minister of Defense Julián García Vargas. Faced with the accumulation of scandals, the leader of CiU and president of the Generalitat de Catalunya, Jordi Pujol, withdrew the parliamentary support of the CiU deputies to the government, leaving the latter in a minority in the Cortes. The president of the government Felipe González had no choice but to call general elections for March 1996. The People's Party won the elections ─ it obtained 156 deputies, 15 more than the PSOE ─ and thus achieved its goal of ousting the Socialists from power, "after trying hard for more than a decade".
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.