Everything below concerns glutathione. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-07-19. Numbers and descriptions here follow the published literature rather than marketing material.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. It occurs in nearly all living cells, with highest concentrations in liver, kidney, and red blood cells, and exists in reduced (GSH) and oxidized disulfide (GSSG) forms. The cysteine thiol group enables reversible oxidation and reduction reactions. This property makes glutathione a central participant in cellular redox balance. The balance between these forms is often used as an indicator of oxidative stress.
Glutathione synthesis proceeds in two ATP-dependent steps catalyzed by glutamate-cysteine ligase and glutathione synthetase. The first step joins glutamate and cysteine to form gamma-glutamylcysteine and is generally rate-limiting. The second step adds glycine to complete the tripeptide. Cysteine availability, feedback inhibition by glutathione, and oxidative conditions influence flux through this pathway. The pathway is conserved across many organisms, and degradation by gamma-glutamyl transpeptidase and related peptidases recycles amino acids for new synthesis.
Within cells, glutathione serves as a cofactor for glutathione peroxidases and glutathione S-transferases. These enzymes reduce hydrogen peroxide and organic peroxides or conjugate electrophilic compounds to the thiol group. The resulting conjugates can be exported and processed through mercapturic acid pathways. Glutathione also contributes to protein thiol homeostasis and to recycling of other antioxidants such as ascorbate. Its precise roles vary by tissue, and many regulatory effects observed in laboratory systems remain difficult to quantify in whole organisms.
Glutathione is synthesized in two ATP-dependent steps. First, gamma-glutamylcysteine synthetase links glutamate and cysteine; second, glutathione synthetase adds glycine to form the complete tripeptide. The pathway is feedback-inhibited by GSH itself, which helps maintain steady intracellular levels. Tissues vary widely in glutathione content, with the liver typically containing the highest concentrations, followed by the kidneys, lungs, and erythrocytes. Because cysteine is often limiting, its availability influences synthesis rates, and regulation of this pathway varies by cell type.
Glutathione serves as a cofactor for several enzymes, including glutathione peroxidase and glutathione S-transferase. These enzymes help reduce hydrogen peroxide and lipid peroxides, and they conjugate reactive electrophiles for excretion. The molecule also acts as a reservoir for cysteine, an amino acid that is prone to oxidation. In addition, glutathione participates in the metabolism of nitric oxide, leukotrienes, and prostaglandins. Its roles extend to cell signaling, apoptosis, and the regulation of protein function through S-glutathionylation.
| Property | Value | Notes |
|---|---|---|
| Common name | Glutathione | Reduced form is abbreviated GSH |
| Chemical class | Tripeptide | Composed of glutamate, cysteine, and glycine |
| Molar mass | 307.32 g/mol | For reduced glutathione |
| CAS Registry Number | 70-18-8 | For reduced L-glutathione |
| Appearance | White crystalline powder | Typical solid reference material |
Synthesis occurs in two ATP-dependent steps. The enzyme glutamate-cysteine ligase joins glutamate and cysteine to form gamma-glutamylcysteine, and glutathione synthetase adds glycine. The first step is rate-limiting and is influenced by cysteine availability and feedback inhibition by GSH. Breakdown involves gamma-glutamyl transferase and subsequent peptidases, which release constituent amino acids for reuse. Because turnover differs among tissues, measurements from blood, plasma, and tissues are not directly interchangeable. Research continues to clarify how compartment-specific pools are regulated in health and disease.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. It contains an unusual gamma-glutamyl bond between glutamate and cysteine, which resists cleavage by many peptidases. The reduced form, GSH, carries a thiol group on cysteine and is the dominant intracellular form in most cells. Its structure allows it to participate in redox reactions and to serve as a sulfur donor. The oxidized form, GSSG, consists of two GSH molecules joined by a disulfide bond.
In cells, glutathione helps maintain the reducing environment of the cytosol and supports enzymes that counteract reactive oxygen species. It acts as a cofactor for glutathione peroxidases, which reduce hydrogen peroxide and lipid peroxides, and for glutathione S-transferases, which conjugate electrophiles. The ratio of GSH to GSSG is often used as an indicator of oxidative stress, although the ratio can vary by compartment and cell type. Glutathione also stores cysteine, an amino acid that can be limiting for protein synthesis and antioxidant defense.
Commercial glutathione is available in research-grade, food-grade, and supplement-grade forms, and purity specifications differ accordingly. Certificates of analysis commonly report identity by nuclear magnetic resonance or mass spectrometry, purity by HPLC, residual solvents, and heavy metals. Reference standards with assigned purity support calibration, while isotopically labeled glutathione can serve as an internal standard for mass spectrometry. For supplements, label claims may not be independently verified, and regulatory oversight varies by country. Verification often involves third-party testing for identity, potency, and contaminants.
Quantifying glutathione requires distinguishing GSH from GSSG and preventing oxidation during sample preparation. Common approaches include the enzymatic recycling assay, often called the Tietze method, which measures total glutathione after converting GSSG to GSH. HPLC with ultraviolet or fluorescence detection and LC-MS/MS can separate and quantify both forms, sometimes after derivatization of the thiol group. Blood, plasma, and tissue samples differ in matrix and baseline concentrations, so method validation must account for recovery, linearity, and interference. No single assay is universally standard.
About 20,000 protein-coding genes are expressed in human cells: 70% of these genes are expressed in thyroid cells. Two-hundred and fifty of these genes are more specifically expressed in the thyroid, and about 20 genes are highly thyroid specific. In the follicular cells, the proteins synthesized by these genes direct thyroid hormone synthesis—thyroglobulin, TPO, and IYD; while in the parafollicular c-cells, they direct calcitonin synthesis—CALCA, and CALCB.
In the Meiji period, Japanese clothes began to be westernized and the number of people who wore kimono decreased, so the craftsmen who made netsuke and kiseru with ivory and wood lost their demand. Therefore, they tried to create a new field, ivory sculptures for interior decoration, and many elaborate works were exported to foreign countries or purchased by the Imperial Family. In particular, the works of Ishikawa Komei and Asahi Gyokuzan won praise in Japan.
As of 2019, GSK-3 is the only type of glycogen synthase kinase named and recognized. The gene symbols for GSK1 and GSK2 have been withdrawn by the HUGO Gene Nomenclature Committee (HGNC), and no new names for these "genes" nor their locations have been specified.
Beyond minor actions against French imperial interests, the Napoleonic Wars were much less global in their scope than preceding conflicts such as the Seven Years' War, which historians term a "world war".
Sources: en.wikipedia.org
== Mosaic Diagnostics, formerly Great Plains Laboratory == William Shaw's laboratory is known for performing nonstandard tests which have been used by alternative medicine practitioners to support discredited diagnoses. Great Plains Laboratory's urine mycotoxin test is not validated nor recommended for diagnosing any condition. In May 2020, early in the COVID-19 pandemic, Great Plains marketed unproven antibody tests.
== Gliding scandals == During the 2020 Women's World Gliding Championships at Lake Keepit, Australia, the home team captain Terry Cubley (Executive Officer of the GFA) was charged with unsporting behaviour for hacking the official tracking system to bypass the mandatory 15 minute delay and forward real time competitors' positions to his team, granting a tactical advantage. An investigation revealed that Matt Gage had been closely involved with the developers of the tracking system, and was aware of an undocumented back door that allowed the team captain (Terry Cubley) to bypass the 15 minute delay. This real-time information was relayed by the team captain over the radio to the Australian pilots. This was the first time in the sport's history that an entire team had been penalised for unsporting behaviour, with the Competition Director applying a penalty of 25 points per pilot per day. Controversially the pilots involved were spared disqualification only receiving a relatively trivial points reduction (compared to a competing pilot who was disqualified for infringing airspace earlier in the competition). Following a subsequent GFA investigation two of the Australian Team admitted to cheating and the GFA made a formal apology to the FAI and the wider gliding community. Terry Cubley was removed from his role as Vice President of the IGC, but chose to remain as Executive Officer of the GFA . The pilots involved chose to appeal against this decision, resulting in the longest and most comprehensive investigation in the FAIs history.
=== Pregnancy === Ketoconazole is categorized as pregnancy category C (Risk not ruled out) in the US. Research in animals has shown it to cause teratogenesis when administered in high doses. A subsequent trial in Europe failed to show a risk to infants of mothers receiving ketoconazole.
=== Hart House === In August 2022, Hart debuted a vegan restaurant, Hart House, to compete with fast-food chains by "offering flavorful plant-based alternatives". The restaurant opened in Los Angeles, California, about a mile from Los Angeles International Airport (LAX), with a simple menu of veggie burgers and Chick'n products. The restaurant's offerings are claimed to be "entirely free of cholesterol, antibiotics, hormones, artificial colors, preservatives, high-fructose corn syrup, or trans fats", and inspired by Hart's own "health nut" lifestyle. Hart opened a second location in Monrovia, California, in November 2022, a third on Sunset Boulevard in Hollywood, California, in May 2023, and a fourth location near the University of Southern California campus in June 2023. All locations closed in September 2024.
(which is true for all aqueous solutions), and the constraint that the solution must be electrically neutral, i.e., the overall charge of dissolved positive ions [Ca2+] + 2 [H+] must be cancelled out by the overall charge of dissolved negative ions [HCO−3] + [CO2−3] + [OH−], make it possible to solve simultaneously for the remaining five unknown concentrations (the previously mentioned form of the neutrality is valid only if calcium carbonate has been put in contact with pure water or with a neutral pH solution; in the case where the initial water solvent pH is not neutral, the balance is not neutral). The adjacent table shows the result for [Ca2+] and [H+] (in the form of pH) as a function of ambient partial pressure of CO2 (Ksp = 4.47×10−9 has been taken for the calculation).
Sources: en.wikipedia.org
GSH is the reduced thiol form, while GSSG is the disulfide-linked oxidized dimer. The GSH:GSSG ratio is used as a redox indicator, though the ratio can vary with sample handling and cell type.
Glutathione is present in many foods, including meats, poultry, fish, some vegetables, and fruits. Cooking, storage, and digestion affect the amounts available for absorption.
Yes, both enzymatic steps in glutathione synthesis consume ATP. The first step, catalyzed by glutamate-cysteine ligase, is usually rate-limiting.
Glutathione is a tripeptide of three amino acids: glutamate, cysteine, and glycine. The cysteine residue provides the sulfhydryl group that gives the molecule its reducing properties.