A practical reference on Gly-His-Lys: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-07-28 and is reviewed periodically as new material appears.
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.
Material described as GHK-Cu appears in several distinct markets, including cosmetic ingredients, laboratory reagents, and consumer products, and the quality expectations attached to each differ. A certificate of analysis generally reports peptide purity by chromatography, copper content, appearance, and residual solvents or counterions. Counterion identity matters, because the complex is usually supplied as an acetate or a similar salt, and the counterion contributes to the measured mass. Independent verification of sequence and metal stoichiometry is advisable when a material is used for quantitative work. Batch-to-batch variation is common and should be documented rather than assumed negligible.
Copper peptide solutions tend to resist degradation better than many free peptides, because the bound metal protects the N-terminus and reduces susceptibility to some peptidases. Backbone hydrolysis, oxidation of the histidine imidazole ring, and photochemical reactions remain the principal degradation routes. Aqueous solutions are generally most stable near neutral to mildly acidic pH, while strongly alkaline conditions accelerate hydrolysis. Light exposure is usually avoided, since both the peptide and the copper center can take part in photochemical processes. Stability data published by suppliers often describe short-term behavior rather than multi-year shelf life.
| Property | Value | Notes |
|---|---|---|
| Solubility | Soluble in water | Free peptide differs from the complex |
| Typical storage | approx. −20 °C, desiccated | Protect from light and moisture |
| Primary purity method | RP-HPLC with MS | Confirms peptide identity |
| Copper assay | ICP-MS or AAS | Measured separately from peptide purity |
| Main degradation routes | Metal loss, hydrolysis, oxidation | Rate depends on pH and matrix |
Quality specifications for research material commonly state peptide purity, copper stoichiometry, counter-ion identity, and residual water content. Frequent counter-ions include acetate and trifluoroacetate, which differ in mass and in their effect on solubility and handling. Whether batch-to-batch differences in reported responses trace to these parameters or to assay conditions remains an open question, since published comparisons rarely control for all of them at once. Independent verification therefore normally pairs a purity measurement with an elemental copper measurement on the same lot.
Practical handling notes centre on limiting exposure to water, oxygen, and repeated temperature cycling. Weighed powder is often equilibrated to room temperature before opening to avoid condensation on the solid. Working solutions are typically divided into single-use aliquots and frozen rather than stored refrigerated for long periods. Reported shelf lives vary widely between laboratories, and no single set of conditions is universally treated as a reference standard, which complicates direct comparison of published stability figures.
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.
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 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.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide sequence is often abbreviated Gly-His-Lys, and the copper is bound through the histidine imidazole nitrogen and adjacent peptide nitrogens. The complex is frequently described as a 1:1 peptide-to-copper species. It occurs naturally in human plasma, saliva, and urine at low concentrations. Its endogenous levels have been reported to decline with age, although the precise physiological role of that change remains an open question.
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.
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=== Defense against infections === PGLYRP2 plays a limited role in host defense against infections. PGLYRP2-deficient mice are more sensitive to Pseudomonas aeruginosa-induced keratitis and Streptococcus pneumoniae-induced pneumonia and sepsis. However, PGLYRP2-deficient mice did not show a changed susceptibility to systemic Escherichia coli, Staphylococcus aureus, and Candida albicans infections or intestinal Salmonella enterica infection, although the latter was accompanied by increased inflammation in the cecum. Although PGLYRP2 is not directly bacteriolytic, it has antibacterial activity against both Gram-positive and Gram-negative bacteria and Chlamydia trachomatis. Human and mouse PGLYRP2 promote hepatitis B virus (HBV) clearance in vitro in hepatocytes and in HBV-infected mice. PGLYRP2 through its HBV DNA-binding domain recognizes covalently closed circular DNA (cccDNA) of HBV sequestering it in the nucleus and separating it from the cellular viral replication machinery. Additionally, PGLYRP2 suppresses HBV capsid assembly by directly interacting through its PGRP domain with the viral capsid and promoting secretion of the PGLYRP2-HBV capsid complexes.
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=== Into Germany === After helping to secure the Ruhr, the 82nd Airborne Division took over Ludwigslust past the Elbe River, accepting the surrender of over 150,000 men of Lieutenant General Kurt von Tippelskirch's 21st Army on 2 May 1945. General Omar Bradley, commanding the US 12th Army Group, stated in a 1975 interview with Gavin that Field Marshal Sir Bernard Montgomery, commanding the Anglo-Canadian 21st Army Group, had told him that German opposition was too great to cross the Elbe. When Gavin's 82nd crossed the river, in company with the British 6th Airborne Division, the 82nd Airborne Division moved 36 miles in one day and captured over 100,000 troops, causing great laughter in Bradley's 12th Army Group headquarters.
Temperatures in the tank were off the scale beyond 25 °C (77 °F), and the pressure in the tank was indicated at 280 kilopascals (40 psi). One employee witnessed a concrete slab above tank E610 crack as the emergency relief valve burst open, and pressure in the tank continued to increase to 380 kilopascals (55 psi), despite atmospheric venting of toxic MIC gas having begun. Direct atmospheric venting should have been prevented or at least partially mitigated by at least three safety devices which were malfunctioning, not in use, insufficiently sized, or otherwise rendered inoperable:
Sources: en.wikipedia.org
Sinecatechins (Veregen) was the first botanical drug approved in the US in 2006; a green tea extract, for genital warts Crofelemer (Mytesi), approved by the FDA in 2012, an extract of "dragon's blood" sap of the Croton lechleri plant, for diarrhea in people with HIV/AIDS Nabiximols (USAN, trade name Sativex) is a specific extract of Cannabis approved as a botanical drug in the United Kingdom as a mouth spray for people with multiple sclerosis, who can use it to alleviate neuropathic pain, spasticity, overactive bladder, and other symptoms; it was developed by the UK company GW Pharmaceuticals Menerba is a botanical drug candidate consisting of 22 herbs that have been used historically in traditional Chinese medicine that act as a selective estrogen receptor modulator. As of 2015 the FDA had approved Bionovo's chemical manufacturing and controls and Menerba was in a Phase III clinical trial as a potential treatment to relieve hot flashes associated with menopause.
== N == NAA – Neutron activation analysis ND – Neutron diffraction NDP – Neutron depth profiling NEXAFS – Near edge X-ray absorption fine structure NIS – Nuclear inelastic scattering/absorption NMR – Nuclear magnetic resonance spectroscopy NOESY – Nuclear Overhauser effect spectroscopy NRA – Nuclear reaction analysis NSOM – Near-field optical microscopy
==== Effects ==== Compound 22 increases the firing rate of dopaminergic neurons in mouse ventral tegmental area (VTA) slices ex vivo similarly to the TAAR1 antagonist EPPTB. It increased the firing rate by 88% at a concentration of 100 μM, whereas EPPTB increased the firing rate by 74% at a concentration of 10 nM. Compound 22 decreased basal locomotor activity in mice in vivo significantly by 58% at 5 mg/kg and non-significantly by 26% at 30 mg/kg. It was not found to stimulate locomotion at any dose. In subsequent experiments, compound 22 did not significantly affect locomotor activity at 5 or 25 mg/kg in either normal mice or TAAR1 knockout mice. The drug dose-dependently enhanced amphetamine-induced hyperlocomotion in mice. The increases were 28% at 5 mg/kg, 44% at 15 mg/kg, 57% at 20 mg/kg, and 77% at 30 mg/kg, but no difference at 50 mg/kg. Compound 22 likewise potentiated cocaine-induced hyperlocomotion in mice. The increases were 77% at 5 mg/kg, 84% at 15 mg/kg, and 124% at 25 mg/kg. Compound 22 augmented amphetamine- and cocaine-induced stereotypy as well. In subsequent experiments, compound 22 potentiated amphetamine-induced hyperlocomotion in normal mice by 44% at a dose of 5 mg/kg but had no significant effect at doses of 2.5 and 15 mg/kg. In TAAR1 knockout mice, compound 22 augmented amphetamine-induced hyperlocomotion by 84% at a dose of 15 mg/kg. The drug dose-dependently potentiated cocaine-induced hyperlocomotion at doses of 5, 15, and 25 mg/kg to similar extents in both normal mice and TAAR1 knockout mice.
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Sources: en.wikipedia.org
The colour comes from electronic transitions in the coordinated copper(II) ion. Ligand field effects absorb part of the visible spectrum. A colourless or greenish sample may indicate degraded material.
Copper can be displaced by other metal ions, by strong chelating agents, or by low pH. Samples exposed to these conditions may contain a mixture of free peptide and complex. Analytical testing is the only reliable way to confirm the bound fraction.
Solution storage generally shortens shelf life compared with the dry powder. Hydrolysis and oxidation proceed faster in aqueous media. Where solutions are used, cold storage and short holding times reduce measurable change.
The solid is typically held cold and dry, and solutions are kept for shorter periods because hydrolysis proceeds in water. Repeated freeze-thaw cycles are usually avoided, since they can degrade both the peptide and the complex. Container material and headspace also affect how long a sample remains unchanged.