If you have been reading about stoichiometry and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-12-24. Numbers and descriptions here follow the published literature rather than marketing material.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide backbone consists of glycine, histidine, and lysine joined in that order. Copper is held through the imidazole nitrogen of histidine and the alpha-amino group at the N-terminus, which together produce a square-planar arrangement around the metal center. The solid appears blue to violet, a color that originates from d-d electronic transitions within the copper coordination sphere. The complex is indexed under CAS number 89030-95-5.
The sequence now called GHK was first reported in the early 1970s after isolation from human plasma, where it was noted to influence liver cell behavior in laboratory preparations. Later work described a copper-binding form and its activity in fibroblast and wound-model experiments. Review articles frequently group the substance with other copper peptides. Concentrations in blood appear to fall with age in several small surveys, although the reason for this trend is not settled. Whether such a decline carries functional consequences remains an open question.
Published work on GHK-Cu concentrates largely on cell culture systems rather than whole organisms. Frequently used endpoints include collagen synthesis, expression of matrix metalloproteinases, and migration of fibroblasts. Some reports describe antioxidant behavior, while others stress delivery of copper into cells. These mechanisms are proposed rather than demonstrated, and the relative weight of each pathway is unclear. Human trials are few and generally small, so laboratory findings should not be read as confirmed clinical results.
The copper-binding activity of this sequence was described in the 1970s during studies of liver tissue and plasma factors. Early work identified the peptide as a component that influenced copper uptake by cells and that appeared in wound fluid. Later investigations examined its presence across species, reporting the same chain in human and animal samples. A decline in measured concentration with age became a recurring observation, although the underlying causes remain incompletely characterised.
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) peptide complex | Peptide chain coordinated to a single metal ion |
| CAS number | 89030-95-5 | Indexed for the peptide-copper complex |
| Molecular formula | C14H22CuN6O4 | Approximate formula for a one-to-one complex |
| Appearance | Blue to violet solid | Color from copper d-d transitions |
| Solubility class | Freely soluble in water | Also dispersible in some polar solvents |
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.
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.
Characterizing GHK-Cu requires methods that distinguish the intact complex from free peptide and unbound copper. UV-visible absorption around 600 nm provides a rapid check for copper coordination, while circular dichroism reports on peptide secondary structure. Mass spectrometry confirms the peptide mass and can detect copper adducts under carefully controlled conditions. Electron paramagnetic resonance is particularly informative for Cu(II) because it reveals the ligand field symmetry. No single technique fully defines the complex, so laboratories combine orthogonal methods.
Stability of GHK-Cu in solution depends on pH, temperature, buffer composition, and oxygen exposure. The copper center can undergo reduction or dissociation, especially in the presence of strong metal chelators such as EDTA. Aqueous solutions are often prepared fresh or stored frozen to limit degradation. Lyophilized solid is more stable than liquid formulations, but it can absorb moisture and should be kept dry. Light exposure may also affect copper complexes, though the effect is often modest.
Purity assessment typically involves high-performance liquid chromatography for the peptide and atomic spectroscopy for copper content. The ratio of copper to peptide is a key quality parameter; a value near one indicates proper stoichiometry. Impurities can include free peptide, copper salts, and truncated sequences from synthesis. Because the complex is dynamic, sample preparation and mobile-phase conditions can shift the observed species. Reported purity values therefore depend on the analytical method and should be interpreted with that context.
=== Elevated potassium === Hyperkalemia develops when there is excess production (oral intake, tissue breakdown) or ineffective elimination of potassium. Ineffective elimination can be hormonal (in aldosterone deficiency) or due to causes in the kidney that impair excretion. Increased extracellular potassium levels result in depolarization of the membrane potentials of cells due to the increase in the equilibrium potential of potassium. This depolarization opens some voltage-gated sodium channels, but also increases the inactivation at the same time. Since depolarization due to concentration change is slow, it never generates an action potential by itself; instead, it results in accommodation. Above a certain level of potassium, the depolarization inactivates sodium channels, opens potassium channels, thus the cells become refractory. This leads to the impairment of neuromuscular, cardiac, and gastrointestinal organ systems. Of most concern is the impairment of cardiac conduction, which can cause ventricular fibrillation and/or abnormally slow heart rhythms.
Quercetin: Quercetin (a flavonoid found in vegan food) supplements, has been suggested to treat baldness. A 2012 study demonstrated that alopecia areata could be used to prevent ant treated with quercetin in mice. Quercetin is found in onions primarily in the peel and the first scaly leaf but not in the flesh. Onion bulb size or weight does not appear to be affected by quercetin concentration. A 2020 study demonstrated that quercitrin stimulated hair shaft growth in cultured human hair follicles. Volatile compounds responsible for pungency and tearing in onions when they are cut (e.g. syn-propanethial S-oxide gas). However, no formal studies have been conducted to evaluate if these compounds promote hair growth or if they help other compounds to penetrate the skin to form hair follicles. To use the volatile compounds: Onions must be extracted and applied topically quickly before the volatile compounds evaporate. The extract will cause tearing eyes, but it can be prevented with a shower cap, or a pair of swimming goggles. To discard the volatile compounds: The onion juice is extracted and stored for a short while to evaporate the volatile compounds. The extract will not cause tearing eyes. Also, both genetically modified, and plant breed onions have been produced with significantly reduced levels of tear-inducing lachrymatory factor.
=== Classification === Malignant peripheral nerve sheath tumors are a rare type of cancer that arise from the soft tissue that surrounds nerves. They are a type of sarcoma. Most malignant peripheral nerve sheath tumors arise from the nerve plexuses that distribute nerves into the limbs—the brachial and lumbar plexuses—or from nerves as they arise from the trunk.
== Treatment == The main goal of treatment is to treat shock and preserve kidney function. Initially, this is done through the administration of generous amounts of intravenous fluids, usually isotonic saline (0.9% weight per volume sodium chloride solution). In victims of crush syndrome, it is recommended to administer intravenous fluids even before they are extracted from collapsed structures. This will ensure sufficient circulating volume to deal with the muscle cell swelling (which typically commences when blood supply is restored), and to prevent the deposition of myoglobin in the kidneys. Amounts of 6 to 12 liters over 24 hours are recommended. The rate of fluid administration may be altered to achieve a high urine output (200–300 mL/h in adults), unless there are other reasons why this might lead to complications, such as a history of heart failure. While many sources recommend additional intravenous agents to reduce damage to the kidney, most of the evidence supporting this practice comes from animal studies, and is inconsistent and conflicting. Mannitol acts by osmosis to enhance urine production and is thought to prevent myoglobin deposition in the kidney, but its efficacy has not been shown in studies, and there is a risk of worsening kidney function.
Sources: en.wikipedia.org
Glutathione S-transferase A3 is an enzyme that in humans is encoded by the GSTA3 gene. Cytosolic and membrane-bound forms of glutathione S-transferase are encoded by two distinct supergene families. These enzymes are involved in cellular defense against toxic, carcinogenic, and pharmacologically active electrophilic compounds. At present, eight distinct classes of the soluble cytoplasmic mammalian glutathione S-transferases have been identified: alpha, kappa, mu, omega, pi, sigma, theta and zeta. This gene encodes a glutathione S-transferase belonging to the alpha class genes that are located in a cluster mapped to chromosome 6. Genes of the alpha class are highly related and encode enzymes with glutathione peroxidase activity. However, during evolution, this alpha class gene diverged accumulating mutations in the active site that resulted in differences in substrate specificity and catalytic activity. The enzyme encoded by this gene catalyzes the double bond isomerization of precursors for progesterone and testosterone during the biosynthesis of steroid hormones. An additional transcript variant has been identified, but its full length sequence has not been determined.
=== Archaea === Archaea use proteases to regulate various cellular processes from cell-signaling, metabolism, secretion and protein quality control. Only two ATP-dependent proteases are found in archaea: the membrane associated LonB protease and a soluble 20S proteosome complex.
== Causes == While the mechanism of the disease has yet to be fully elucidated, the leading hypothesis is that AAV (ANCA Associated Vasculitis) develops in patients with a genetic predisposition when an unknown cause triggers the production of p-ANCA. These antibodies will circulate at low levels until an environmental trigger—such as infection, malignancy, or drug therapy, causes the upregulation of neutrophils. The neutrophils bind to p-ANCAs and subsequently release inflammatory cytokines, reactive oxygen species and lytic enzymes that cause endothelial injury resulting to inflammation and necrosis of the small vessels. The damage that is caused in the kidneys is specifically called necrotizing and crescentic glomerulonephritis.
Sources: en.wikipedia.org
=== Major users' response === Beginning around 2000, as the scientific evidence and public concern about trans fat increased, major American users of trans fat began to switch to safer alternatives. The process received a large boost in 2003 when the FDA announced it would require trans fat labeling on packaged food starting in 2006. Packaged food companies then faced the choice of either eliminating trans fat from their products, or having to declare the trans fat on their nutrition label. Lawsuits in the U.S. against trans fat users also encouraged its removal. Major American fast food chains including McDonald's, Burger King, KFC and Wendy's reduced and then removed partially hydrogenated oils (containing artificial trans fats) by 2009. This was a major step toward trans fat removal, as french fries were one of the largest sources of trans fat in the American diet, with a large serving of fries typically having about 6 grams of trans fat until around 2007. Two other events were important in the removal of trans fat. First, in 2013 the FDA announced it planned to completely ban artificial trans fat in the form of partially hydrogenated oil. Second, soon after this, Walmart informed its suppliers they needed to remove trans fat by 2015 if they wanted to continue to sell their products at its stores. As Walmart is the largest brick-and-mortar retailer in the U.S., mainstream food brands had little choice but to comply.
=== 24 December === The RSF captured the towns of Abu Qamra and Ambara, while the SAF and JDF withdrew towards Tine and Karnoi along the Chadian border which are the last areas in Darfur under SAF control. The RSF also claimed to have recaptured Alouba, two days after it was captured by the SAF.
==== Biofilm management ==== We are developing greater insight into the association between delayed healing and the presence of biofilm. The relationship between delayed healing and the need for debridement is also being acknowledged. It has been suggested that the presence of wound slough provides an indication of biofilm presence, therefore, indicating the need to reduce the wound bioburden. Methods of effectively managing wound biofilms have been reported and include the use of topical agents, systemic antibiotics and regular episodes of debridement. Despite these advances it has been recognised that indiscriminate and widespread use of antibiotics both inside and outside of medicine is playing a substantial role in the emergence of bacterial resistance. On a more positive note, antiseptics have been reported to possess a clear cut role in the control of wound bioburden where there are indications or risk of infection.
Sources: en.wikipedia.org
It is the copper complex of the tripeptide glycyl-L-histidyl-lysine. The metal ion is held by the histidine imidazole group and the peptide N-terminus. Most research on it concerns skin and wound models.
The tripeptide was first isolated from human plasma and has also been reported in saliva and urine. Plasma levels appear to decline with age in some small studies. Those observations rest on limited sample sizes.
It is not authorized as a systemic medicine in most countries. Cosmetic preparations list it as an ingredient rather than an active pharmaceutical substance. Legal status therefore differs by jurisdiction.
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.