Gly-His-Lys 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 2025-10-16. Numbers and descriptions here follow the published literature rather than marketing material.
Copper(II) binds the peptide through four nitrogen donors: the terminal amino group, the imidazole nitrogen of histidine, and two deprotonated amide nitrogens of the peptide backbone. This tetradentate arrangement gives a roughly square-planar geometry, the thermodynamically favoured form near neutral pH. Because the amide nitrogens must lose a proton before they can coordinate, complex formation is strongly pH-dependent, and the fully coordinated species dominates only above mildly acidic conditions. Electronic transitions within the copper d orbital set produce the characteristic blue to violet colour in aqueous solution.
Endogenous GHK occurs in blood plasma, saliva, and urine, and reported plasma concentrations decline with age in several studies. Researchers have proposed that the peptide acts as a copper carrier that delivers the metal to cells and to sites of injury. That transport role is a hypothesis supported by binding measurements and tissue-distribution data rather than a settled mechanism, and the peptide is generally described as a minor contributor to total plasma copper transport. Values reported in wound fluid and certain tissue extracts are higher than in circulating plasma.
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 |
|---|---|---|
| Chemical class | Copper(II)-tripeptide complex | One peptide ligand with one coordinated metal centre |
| Peptide sequence | Gly-His-Lys | Three residues written in one-letter notation |
| Free peptide mass | 340.4 g/mol | Metal-free GHK; the complex has a higher mass |
| Appearance | Blue to violet solid or solution | Colour originates from copper d orbital transitions |
| Storage | Desiccated, -20 °C, protected from light | Dry powder is more stable than dissolved material |
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.
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.
The compound was first isolated from human plasma by the biochemist Loren Pickart in 1973. Early work identified it as a factor that altered the behavior of cultured liver cells, and later studies linked it to connective tissue and wound-related processes. Reported plasma concentrations fall markedly between roughly age twenty and age sixty, a pattern that generated interest in copper peptide biology. Whether that decline has functional consequences remains an open question, because differences observed across age groups do not by themselves establish causation. Research interest later expanded into cosmetic and tissue-culture settings.
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.
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.
Research interest in GHK-Cu centers on its ability to deliver copper and to influence cellular processes in laboratory models. In cell culture and animal studies, the complex has been linked to collagen synthesis, antioxidant enzyme activity, and expression of genes associated with tissue remodeling. These effects are not equivalent to proven clinical outcomes. The mechanisms proposed include copper transfer to cuproenzymes, modulation of growth factor signaling, and interactions with extracellular matrix components. How much of the observed activity depends on intact GHK-Cu versus free copper or free peptide is not fully resolved.
The compound entered scientific literature in the 1970s, when plasma factors with copper-binding activity were isolated and characterized. Later work expanded into wound healing, skin biology, and cosmetic formulation, where copper tripeptide-1 became a recognized ingredient name. Most published studies remain preclinical or small-scale, and findings are often reported in specialized dermatology or peptide journals. Regulatory treatment varies: some jurisdictions allow it as a cosmetic ingredient, while research-grade material is sold for laboratory use. Questions about optimal delivery, target tissues, and long-term effects continue to be investigated rather than settled.
Southern Association, previously Class A1 (1936–1945) Texas League, previously Class A1 (1936–1942; idle for three seasons during World War II) The Texas League remained in Double-A for the next 75 years. During this time, there were limited changes to leagues at the Double-A level:
=== Laboratory methods === In general, on the typical laboratory scale, the direct reaction of a haloalkane with sodium hydrosulfide is inefficient owing to the competing formation of sulfides (overalkylation). Instead, alkyl halides are converted to thiols via an S-alkylation of thiourea. This multistep, one-pot process proceeds via the intermediacy of the isothiouronium salt, which is hydrolyzed in a separate step:
== History == The Code for Intact Stability was first issued in 1993 under IMO resolution A.749(18)). In 2008, the Code was updated by the IMO. In December 2019, amendments to the Code were adopted that entered into force on 1 January 2020. These amendments related to ships engaged in anchor handling operations and to ships carrying out lifting and towing operations.
== External links == Observations Support Homochirality Theory. Photonics TechnologyWorld November 1998. Origins of Homochirality Archived 2010-08-21 at the Wayback Machine. Conference in Nordita Stockholm, February 2008.
Lysine is also often involved in histone modifications, and thus, impacts the epigenome. The ε-amino group often participates in hydrogen bonding and as a general base in catalysis. The ε-ammonium group (−NH+3) is attached to the fourth carbon from the α-carbon, which is attached to the carboxyl (−COOH) group. Due to its importance in several biological processes, a lack of lysine can lead to several disease states including defective connective tissues, impaired fatty acid metabolism, anaemia, and systemic protein-energy deficiency. In contrast, an overabundance of lysine, caused by ineffective catabolism, can cause severe neurological disorders. Lysine was first isolated by the German biological chemist Ferdinand Heinrich Edmund Drechsel in 1889 from hydrolysis of the protein casein, and thus named it Lysin, from Greek λύσις (lysis) 'loosening'. In 1902, the German chemists Emil Fischer and Fritz Weigert determined lysine's chemical structure by synthesizing it. The one-letter symbol K was assigned to lysine for being alphabetically nearest, with L being assigned to the structurally simpler leucine, and M to methionine.
Sources: en.wikipedia.org
and Canada that contain aspartame must be labeled: "Phenylketonurics: Contains phenylalanine." In the UK, foods containing aspartame must carry ingredient panels that refer to the presence of "aspartame or E951" and they must be labeled with a warning "Contains a source of phenylalanine." In Brazil, the label "Contém Fenilalanina" (Portuguese for "Contains Phenylalanine") is mandatory in products which contain it. These warnings are placed to help individuals avoid such foods.
=== Origins (1992–2004) === Julien Rour Chanut grew up in the Essonne department, south of Paris, in France. Mehdi Birouk Thépegnier, born in Morocco (Maghreb), arrived in France at the age of 12. They met in 1992 at a college in Essonne and became friends. Chanut and Thépegnier were passionate about 1990s hardcore punk, heavy metal and grunge. The hardcore scene consisting of bands such as Confusion, Integrity, Only Living Witness, Section 8, and Sheer Terror, and the do-it-yourself philosophy associated with this culture, motivated them to perform music. Chanut found his path between the ages of 13 and 14 by beginning to play hardcore punk. The two friends first stepped onto the stage at around 15 or 16. They grew up in the hardcore punk scene of the 1990s. Thépegnier was a member of Mouvement Colère (lit. 'Anger Movement') and later a bassist in Drowning, which toured as the opening act for All Out War and Merauder. Over time, Chanut and Thépegnier performed in various local bands, including Arkangel (band), Es La Guerilla and Rising Dust. Clément Hanvic was part of their circle; he was the singer of Knockoutz and the bassist of L'Esprit du Clan (lit. 'The Spirit of the Clan'), and performed with Es La Guerilla. The bassist for Knockoutz and Es La Guerilla was Kéo Nackphouminh. Sid-Ahmed Azzouni was a guitarist in Es La Guerilla. After playing electric bass for a while, Thépegnier switched to drums.
Acapulco, with its natural harbor, had been settled by indigenous peoples for thousands of years and later established as a port by Hernán Cortés in 1523. By Humboldt’s visit, the city had diminished in significance, with a small population and little commercial activity. Upon arrival, Humboldt used his instruments to correct geographic errors caused by local currents and earthquakes, further improving navigation and mapping accuracy. Humboldt’s primary reason for coming to New Spain was to secure passage to the Philippines, but he viewed Mexico as a vital subject for study. At the start of the nineteenth century, New Spain was a populous and prosperous colony, contributing significantly to Spain’s economy through silver, gold, and agricultural production. Humboldt, holding a royal passport, enjoyed unprecedented access to official records and facilities, enabling him to study the country’s economic and political structures thoroughly.
It was definitively accepted by the Fédération Cynologique Internationale in 1954. In the fifteen years from 2007 to 2021, the annual number of new registrations in Germany averaged about 485, with a low of 390 and a high of 607.
Sources: en.wikipedia.org
== Further reading == Al-Hussainy, Abbas Ali Abbas, "The civilized achievements of the Akkadian king Naram-Sin A Research in his Artistic Remains and The Date Formulas", ISIN Journal 3, 2022 Boissier, Alfred, "Inscription de Naram-Sin", Revue d’Assyriologie et d’archéologie Orientale, vol. 16, no. 3, pp. 157–64, 1919 Foster, B. R., "Naram-Sin in Martu and Magan", ARRIM 8, pp. 25–44, 1990 Glassner, J. J., "Naram-Sîn Poliorcète. Les avatars d'une sentence divinatoire", Revue d’Assyriologie et d’archéologie Orientale, vol. 77, no. 1, pp. 3–10, 1983 Grayson, A. Kirk, and Edmond Sollberger, "L’insurrection générale contre Narām-Suen", RA70, pp. 103–128, 1976 Lafont, Bertrand, "Une plaque en argile portant une inscription de Naram-Sin d'Agadé", The Third Millennium. Studies in Early Mesopotamia and Syria in Honor of Walter Sommerfeld and Manfred Krebernik, hrsg. v. Arkhipov, Ilya, Kogan, Leonid, Koslova, Natalia (Cuneiform Monographs 50), pp. 408–416, 2020 Piotr Michalowski, "New Sources concerning the Reign of Naram-Sin", Journal of Cuneiform Studies, vol. 32, no. 4, pp. 233–246, (Oct., 1980) Nassouhi, Essad, "Un vase en albatre de Naram - Sin", Revue d’Assyriologie et d’archéologie Orientale, vol. 22, no. 2, pp. 91–91, 1925 [12] A. Poebel, "The ‘Schachtelsatz’ Construction of the Naram-Sîn Text RA XVI 157f.", Miscellaneous Studies, AS 14; Chicago, pp.23–42, 1947 Powell, Marvin A., "Narām-Sîn, Son of Sargon: Ancient History, Famous Names, and a Famous Babylonian Forgery", Zeitschrift für Assyriologie und Vorderasiatische Archäologie, vol. 81, no. 1-2, pp.
By the spring of 1917, the War was dragging on towards its fourth year, and Zita's brother Prince Sixtus of Bourbon-Parma, a serving officer in the Belgian Army, was a main mover behind a plan for Austria-Hungary to make a separate peace with France. Charles initiated contact with Sixtus through contacts in neutral Switzerland, and Zita wrote a letter inviting him to Vienna. Zita's mother, Maria Antonia, delivered the letter in person. Sixtus arrived with conditions for talks which had been agreed with the French – the restoration to France of Alsace-Lorraine (annexed by Germany after the Franco-Prussian War in 1870); restoration of the independence of Belgium; independence for the kingdom of Serbia; and the handover of Constantinople to Russia. Charles agreed, in principle, to the first three points and wrote a letter to Sixtus dated 25 March 1917 which sent "the secret and unofficial message" to the President of France that "I will use all means and all my personal influence". This attempt at dynastic diplomacy eventually foundered. Germany refused to negotiate over Alsace-Lorraine, and, seeing a Russian collapse on the horizon, was loath to give up the war. Sixtus continued his efforts, even meeting David Lloyd George in London about Italy's territorial demands on Austria in the 1915 Treaty of London, but the Prime Minister could not persuade his generals that Britain should make peace with Austria. Zita managed a personal achievement during this time by stopping the German plans to send airplanes to bomb the home of the King and Queen of Belgium on their name days.
==== OXA-48-like carbapenemases ==== The spread of OXA-48 carbapenem resistance involves both the expansion of successful bacterial clones and the movement of blaOXA-48 between bacteria on mobile genetic elements. The gene is commonly associated with Tn1999-family transposons carried on highly conjugative IncL plasmids, although OXA-48-like genes also occur in other plasmid types and chromosomal contexts. A community outbreak in New Zealand during 2018–2022 involved 25 patients with OXA-48-producing Escherichia coli sequence type 131. Eighteen patients had visited the same community food premises, where four food handlers were also found to be colonized, and whole-genome sequencing demonstrated genomic links between patient and food-handler isolates. Subsequent long-read genomic analysis found that the outbreak lineage had acquired blaOXA-48 on a 7,872-base-pair Col156 plasmid and identified a single IS1-mediated transposition of the resistance gene into the Col156 plasmid backbone. Analysis of global genomic data showed that blaOXA-48 occurs in diverse plasmid and insertion-sequence contexts among Enterobacterales.
Sources: en.wikipedia.org
It consists of a three-amino-acid peptide, glycine-histidine-lysine, bound to one copper(II) ion. The peptide supplies four nitrogen donor atoms, and the resulting complex is stable in neutral aqueous solution. The metal-free peptide is usually called GHK.
The three letters are the standard one-letter codes for glycine, histidine, and lysine. The suffix -Cu indicates the coordinated copper ion. Cosmetic ingredient lists often use the alternative name copper tripeptide-1 for the same complex.
No. Free GHK is the peptide alone, while GHK-Cu contains a bound copper atom. The two differ in colour, charge, and binding behaviour, so any study that measures copper delivery must state which form was used.
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.