Everything below concerns RP-HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-08-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Copper takes part in redox chemistry, and the same property that makes it useful in enzymes can generate reactive oxygen species when the ion is loosely bound. GHK chelates copper through imidazole, amino, and amide nitrogen donors, which reduces the amount of free copper in solution. Whether that chelation is protective, neutral, or harmful in a given tissue is not settled. Laboratory assays report both antioxidant and pro-oxidant behavior, depending on the conditions and the readout used.
Published work on GHK-Cu is dominated by in vitro experiments and small animal studies. Human trials tend to be short and small, with endpoints such as skin appearance rather than clinical outcomes. Review articles often summarize the same underlying laboratory findings, which can make the evidence base look broader than it is. Several basic questions remain open: the concentration of the intact complex in human tissue, the route by which it crosses the skin barrier, and whether effects seen in culture produce measurable changes in people.
Laboratory studies describe GHK-Cu as a source of copper that cells can take up, with reported effects on collagen, elastin, and glycosaminoglycan synthesis in cultured fibroblasts. The peptide also appears in wound-repair research, where it is linked to the activity of matrix metalloproteinases and their inhibitors. These observations come largely from cell and animal models. How directly the complex controls any single pathway in intact human skin remains an open question, and reported effects depend on concentration, vehicle, and exposure time.
| 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 |
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.
Solutions of GHK-Cu respond strongly to pH, redox conditions, and the presence of competing chelators such as EDTA. Below roughly pH 4 the copper tends to dissociate, because the amide nitrogen donors become protonated and can no longer coordinate. Strongly alkaline conditions instead favour hydrolysis and precipitation of copper hydroxide. Dissolved oxygen and light accelerate breakdown of the peptide backbone, and the copper released during that process can catalyse further oxidation, so dry, cold, dark storage is the usual recommendation.
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.
But a problem arose for the NRL researchers because naval materials, e.g., ship-plate steel, are not perfectly elastic but undergo significant plastic deformation at the tip of a crack. One basic assumption in Irwin's linear elastic fracture mechanics is small scale yielding, the condition that the size of the plastic zone is small compared to the crack length. However, this assumption is quite restrictive for certain types of failure in structural steels though such steels can be prone to brittle fracture, which has led to a number of catastrophic failures. Linear-elastic fracture mechanics is of limited practical use for structural steels and Fracture toughness testing can be expensive.
Multisite pain is defined as six or more pain sites from a total of nine possible sites (head, arms, chest, abdomen, upper back, lower back, and legs), for at least three months Moderate to severe sleep problems or fatigue, for at least three months A 2025 review found that challenges and limitations continue, due to patients over- or under-estimating their symptoms, or describing them differently. Some people can move into and out of an FM diagnostic level over time as their symptoms vary.
Renal corpuscle: Liquid enters the nephron system at the Bowman's capsule. Proximal convoluted tubule: It then may reabsorb urea in the thick descending limb. Water is removed from the nephrons by osmosis (and glucose and other ions are pumped out with active transport), gradually raising the concentration in the nephrons. Loop of Henle Descending: The liquid passes from the thin descending limb to the thick ascending limb. Water is constantly released via osmosis. Gradually there is a buildup of osmotic concentration, until 1200 mOsm is reached at the loop tip, but the difference across the membrane is kept small and constant. For example, the liquid at one section inside the thin descending limb is at 400 mOsm while outside it is 401. Further down the descending limb, the inside concentration is 500 while outside it is 501, so a constant difference of 1 mOsm is kept all across the membrane, although the concentration inside and outside are gradually increasing. Loop of Henle Ascending: after the tip (or 'bend') of the loop, the liquid flows in the thin ascending limb. Salt–sodium Na+ and chloride Cl− ions are pumped out of the liquid gradually lowering the concentration in the exiting liquid, but, using the countercurrent multiplier mechanism, always pumping against a constant and small osmotic difference. For example, the pumps at a section close to the bend, pump out from 1000 mOsm inside the ascending limb to 1200 mOsm outside it, with a 200 mOsm across.
Meyer (1940), composer, author, philosopher known for his contributions to the aesthetic theory of music Orrin Keepnews (1943), jazz record producer and winner of the 1988 Grammy Award for Best Album Notes and Best Historical Album Mort Lindsey (1944), musical director for Judy Garland and Merv Griffin Dick Hyman (1948), musical director for Arthur Godfrey; composer or arranger for Hannah and Her Sisters and The Purple Rose of Cairo; Emmy Award winner Philip Springer (1950), composer known for writing the song "Santa Baby" Randy Starr (1951), dentist and composer for Elvis Presley Eric Salzman (1954), composer, producer, critic; founder of the American Music Theater Festival and composer-in-residence of the Center for Contemporary Opera Malcolm Frager (1955), piano virtuoso Mike Berniker (1957), musical producer and winner of nine Grammy Awards Billy Goldenberg (1957), composer and winner of four Emmy Awards John Corigliano (1959), winner of the Pulitzer Prize for Music and Academy Award for Best Original Score Edward Kleban (1959), lyricist for A Chorus Line David Bromberg* (1960s), Grammy Award-nominated musician Art Rosenbaum (1960), Grammy Award-winning art professor and musician at Georgia State University Charles Wuorinen (1961), serialist composer and winner of the Pulitzer Prize for Music for Time's Encomium Charlie Morrow (1962), sound artist and musician Joel Krosnick (1963), chamber musician and member of the Juilliard String Quartet David Rubinson (1963), record and music producer of Apocalypse Now, founder of San Francisco Records and The Automatt recording studio Art Garfunkel (1965), singer of Simon and Garfunkel, famous for the song "The Sound of Silence" Daniel Waitzman (1965), flutist and composer Kenneth Ascher (1966), Academy Award-nominated jazz pianist; writer of "Rainbow Connection" from The Muppet Movie David Schiff (1967), composer Tom Werman (1967), former record producer for Epic Records Billy Cross (1968), guitarist, singer, and producer who lives in Denmark Jon Bauman (1969), "Bowzer" of Sha Na Na James "Plunky" Branch (1969), jazz musician Cameron Brown (1969), jazz bassist Emanuel Ax (1970), concert pianist Marc Copland (1970), jazz pianist and composer Scott Simon (1970), member of Sha Na Na Frederick "Dennis" Greene (1971), member of Sha Na Na; professor of law at the University of Dayton Armen Donelian (1972), jazz pianist Jocko Marcellino (1972), member of Sha Na Na Phil Schaap (1973), Charlie Parker authority and multiple Grammy Award winner for engineering, production, and album notes Eugene Drucker (1973), Grammy Award-winning violinist, member of the Emerson String Quartet Sam Morrison (1973), saxophonist Michael Jeffrey Shapiro (1973), composer and conductor Richard Einhorn (1975), composer, Voices of Light Phil Kline (1975), composer Paul Phillips (1978), conductor, composer, and music scholar at Brown University Erik Friedlander (1982), cellist, son of American photographer Lee Friedlander Robbie Fulks* (1984), Grammy Award-nominated American alternative country singer-songwriter Dave Nachmanoff (1986), award-winning folk singer and sideman to Al Stewart John Bohlinger (1988), musician and music director on NBC program Nashville Star Laura Cantrell (1989), country musician Peter J. Nash (1989), member of 3rd Bass Mac McCaughan (1990), member of indie rockband Superchunk and founder of Merge Records Richard Carrick (1993), pianist, composer, professor at Berklee College of Music Gil Shaham (1993), violinist Jefferson Friedman (1996), composer Tom Kitt (1996), composer, co-winner of the 2010 Pulitzer Prize for Drama and the Tony Award for Best Original Score for his score of the musical Next to Normal R. Luke DuBois (1997), composer and artist Lauryn Hill* (1997), Grammy Award-winning R&B singer and songwriter, and member of The Fugees Sean Lennon* (1997), singer and songwriter, and son of John Lennon and Yoko Ono Orli Shaham (1997), pianist Yelena Dudochkin (1998), Ukrainian-American soprano Scott Hoffman (1999), known by the stage name Babydaddy, member of the rock band Scissor Sisters The Two Man Gentlemen Band, modern musical duo that consists of Fuller Condon (2000) and Andy Bean (2001) Mason Bates (2000), Grammy Award-winning composer Tom Frank (2000), journalist, former member of indie-rock band Jonathan Fire*Eater Hikaru Utada* (2000), Japanese pop star Alicia Keys* (2001), Grammy Award-winning R&B singer and songwriter Brian Weitz (2001), founding member of experimental band Animal Collective Emily and Julia Bruskin (2002), members of the Claremont Trio Ken-David Masur (2002), musical director of the Milwaukee Symphony Orchestra, son of conductor Kurt Masur Ariana Ghez (2003), oboist Nico Muhly (2003), contemporary classical music composer Anna Bulbrook (2004), violinist formerly member of indie band The Airborne Toxic Event Alisa Weilerstein (2004), cellist and 2011 MacArthur Fellow Tristan Perich (2004), contemporary composer and sound artist Peter Cincotti (2005), pianist Ellen Reid (2005), composer and recipient of the 2019 Pulitzer Prize for Music Patrick Higgins (2006), composer, musician, producer Michael Barimo (2006), pop singer and whistler Rostam Batmanglij (2006), member of alt-rock band Vampire Weekend Ezra Koenig (2006), member of alt-rock band Vampire Weekend Chris Tomson (2006), member of alt-rock band Vampire Weekend Chris Baio (2007), member of alt-rock band Vampire Weekend Call Me Ace or Anthony Patterson (2011), rapper Adam Met (2013), member of pop band AJR Danny Mercer (2013), singer, songwriter and producer Nathan Chan (2014), cellist Conrad Tao (2015), composer, pianist, violinist Jack Met* (2019), member of pop band AJR Maude Latour (2022), singer-songwriter Annie Moon (2026), member of a co-ed K-Pop Group ALLDAY PROJECT
Sources: en.wikipedia.org
TCFH (N,N,N’,N’-tetramethylchloroformamidinium hexafluorophosphate) is an electrophilic amidine reagent used to activate a number of functional groups (such as carboxylic acids) for reaction with nucleophilies. TCFH is most commonly used to activate carboxylic acids for reaction with amines in the context of amide bond formation and peptide synthesis.
In the United Kingdom, it is a criminal offence to sell, supply, or import any medicinal product containing kava for human consumption. It is legal to possess kava for personal use or to import it for purposes other than human consumption (e.g., for animals). Until August 2018, Poland was the only EU country with an "outright ban on kava" and where the mere possession of kava was prohibited and may have resulted in a prison sentence. Under the new legislation, kava is no longer listed among prohibited substances and it is therefore legal to possess, import, and consume the plant, but it remains illegal to sell it within Poland for the purpose of human consumption. In the Netherlands the ban was never lifted, and it is still prohibited to prepare, manufacture, or trade kava or goods containing kava. Due to safety concerns, including reports of hepatotoxicity and limitations in clinical evidence, the Committee on Herbal Medicinal Products (HMPC) concluded in 2017 that the benefit-risk balance for the oral use of kava in the treatment of anxiety disorders is unfavorable, and therefore a European Union herbal monograph could not be established.
== Host/implant interactions == Wound healing of the skin and tendons is a complex coordinated process in the body that happens slowly over weeks or even years. A number of products in the market today aim to affect this process positively, although little data is available on their success. The majority of products are still in the development phases where the (often inflammatory) interactions between the host and the implanted devices are being assessed. Implanted ECM biomaterials fall into two general categories based on how they interact with the host. Incorporating devices eventually allow the growth of cells and passage of blood vessels through the matrix, whereas nonincorporating biomaterials are encapsulated by a wall of fused macrophages. In nonincorporating biomaterials such as Permacol, an acellular porcine dermal implant for hernia repair, it is important that the material is not degraded or infiltrated by the immune system. Encapsulated biomaterials that are recognized as foreign can be degraded and/or rejected by the body and migrate to the outside of the body. In incorporated ECM biomaterials, infiltration by the immune system can occur in as few as seven days, leading to rapid degradation of the device volume. In the case of Graftjacket, an allograft from human dermis, the matrix is quickly populated by host cells as vasculature. The device itself decreased more than 60% in volume, and is replaced with host fibroblasts and macrophages.
If early organisms had been driven by the same environmental conditions to evolve similar biochemistry convergently, they might independently have acquired similar genetic sequences. Theobald's "formal test" was accordingly criticised by Takahiro Yonezawa and colleagues for not including consideration of convergence. They argued that Theobald's test was insufficient to distinguish between the competing hypotheses. Theobald has defended his method against this claim, arguing that his tests distinguish between phylogenetic structure and mere sequence similarity. Therefore, Theobald argued, his results show that "real universally conserved proteins are homologous."
p is the pressure ρ is the density and ρ(p) indicates that it is a function of pressure v is the flow speed Ψ is the potential associated with the conservative force field, often the gravitational potential In engineering situations, elevations are generally small compared to the size of the Earth, and the time scales of fluid flow are small enough to consider the equation of state as adiabatic. In this case, the above equation for an ideal gas becomes:
Sources: en.wikipedia.org
== Associated disease states and abnormalities == Abnormal GnSAF bioactivity has been associated with premature surges in LH and LH hypersecretion. Optimal and timely changes in serum LH concentrations are crucial to ensuring the viability of oocytes and implantation after fertilization. For successful implantation of a zygote, the mid-cycle LH surge after the decline of GnSAF and ovulation must correspond with uterine receptivity. Hypersecretion of LH contributes to cycle disturbance, infertility and increased chances of miscarriage. GnSAF has been implicated in polycystic ovary syndrome (PCOS), one of the most common ovarian disorders responsible for causing anovulatory infertility. Approximately 40% of women with PCOS display higher GnRH pulse frequency and tonic hypersecretion of LH due to hypersecretion of androgens from the polycystic ovary. Androgens are readily metabolized to estradiol in the ovaries. The supraphysiological concentrations of estradiol maintains high pituitary responsiveness to GnRH, permitting the hypersecretion of LH. Superovulation is common in women who take medications such as clomiphene citrate, an anti-estrogenic oral medication used to treat infertility. Superovulation is induced in women to increase chances of fertilization and conception in assisted reproductive techniques. In naturally superovulating women, the mid-cycle LH surge is significantly lower compared to that of normal ovulating women due to the presence of GnSAF in the late follicular phase fluid.
=== Circulatory disorders === Diabetic vasculopathy Sepsis with peripheral necrosis Peripheral artery disease which can lead to gangrene A severe deep vein thrombosis (phlegmasia cerulea dolens) can cause compartment syndrome and gangrene
The fucoxanthin dinophyte lineages (including Karlodinium and Karenia) lost their original red algal derived chloroplast, and replaced it with a new chloroplast derived from a haptophyte endosymbiont, making these tertiary plastids. Karlodinium and Karenia probably took up different endosymbionts. Because the haptophyte chloroplast has four membranes, tertiary endosymbiosis would be expected to create a six membraned chloroplast, adding the haptophyte's cell membrane and the dinophyte's phagosomal vacuole. However, the haptophyte was heavily reduced, stripped of a few membranes and its nucleus, leaving only its chloroplast (with its original double membrane), and possibly one or two additional membranes around it. Fucoxanthin-containing chloroplasts are characterized by having the pigment fucoxanthin (actually 19′-hexanoyloxy-fucoxanthin and/or 19′-butanoyloxy-fucoxanthin) and no peridinin. Fucoxanthin is also found in haptophyte chloroplasts, providing evidence of ancestry.
An ingredient in diesel exhaust fluid (DEF), which is 32.5% urea and 67.5% de-ionized water. DEF is sprayed into the exhaust stream of diesel vehicles to break down dangerous NOx emissions into harmless nitrogen and water. A component of animal feed, providing a relatively cheap source of non-protein nitrogen to promote growth. A non-corroding alternative to rock salt for road de-icing. It is often the main ingredient of pet friendly salt substitutes although it is less effective than traditional rock salt or calcium chloride. A main ingredient in hair removers such as Nair and Veet. A browning agent in factory-produced pretzels. An ingredient in some skin cream, moisturizers, hair conditioners, and shampoos. A cloud seeding agent, along with other salts. A flame-proofing agent, commonly used in dry chemical fire extinguisher charges such as the urea-potassium bicarbonate mixture. Along with diammonium phosphate, as a yeast nutrient, for fermentation of sugars into ethanol. A nutrient used by plankton in ocean nourishment experiments for climate engineering purposes. As an additive to extend the working temperature and open time of hide glue. As a solubility-enhancing and moisture-retaining additive to dye baths for textile dyeing or printing. As an optical parametric oscillator in nonlinear optics. To help prepare an alpine skiing course by hardening the snow into a icier surface to maintain the integrity of the course.
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.
It is not approved as a pharmaceutical in major markets and is used mainly as a cosmetic ingredient and a laboratory reagent. Regulatory status varies by country and by the product category in which it appears. Claims about therapeutic effects should be treated separately from permitted cosmetic labeling.