Thiol 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.
Last reviewed on 2026-02-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
Cells synthesize glutathione through two ATP-dependent enzymatic steps. The first step combines glutamate and cysteine to form gamma-glutamylcysteine, catalyzed by glutamate-cysteine ligase. The second step adds glycine, producing the complete tripeptide, catalyzed by glutathione synthetase. Glutathione itself can inhibit the first enzyme, providing negative feedback when levels are high. Because cysteine is often limiting, its availability influences how quickly the pathway proceeds. These reactions occur in the cytosol, and the resulting glutathione can be distributed to other compartments.
Glutathione functions in redox balance, detoxification, and sulfur amino acid storage. It participates in reactions that help maintain ascorbate and protein thiol status. The molecule serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. These enzymes reduce peroxides and conjugate electrophiles, respectively. Glutathione also contributes to the metabolism of xenobiotics and to the transport of cysteine between tissues. How interorgan transport and tissue-specific regulation shape whole-body pools remains an active area of study.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. Its cysteine residue carries a thiol group, which allows the molecule to participate in reduction and oxidation reactions. The compound exists in most living cells, where the reduced form, often abbreviated GSH, is usually more abundant than the oxidized disulfide form, GSSG. Intracellular concentrations are commonly in the millimolar range, while extracellular concentrations are much lower. This uneven distribution supports its role as a major cellular redox buffer.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine, and it is the most abundant non-protein thiol in most living cells. The reduced form, GSH, carries a sulfhydryl group that can donate electrons, while the oxidized form, GSSG, forms when two GSH molecules link via a disulfide bond. The balance between these two forms helps define the cellular redox environment, and their ratio is often used as an indicator of oxidative stress. Because the sulfhydryl group is reactive, glutathione participates in many cellular processes, including detoxification and protein regulation.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C10H17N3O6S | Reduced glutathione (GSH) |
| Molar mass | 307.32 g/mol | Calculated for C10H17N3O6S |
| Appearance | White to off-white powder | Typical solid form |
| Solubility | Water-soluble | Polar tripeptide |
| Common synonyms | GSH; L-glutathione | Gamma-glutamylcysteinylglycine |
Glutathione is a small tripeptide composed of glutamate, cysteine, and glycine, with the unusual gamma-glutamyl linkage between glutamate and cysteine. Its cysteine thiol group makes it a major non-enzymatic antioxidant in cells. The reduced form, GSH, predominates in most intracellular compartments, while the oxidized disulfide form, GSSG, is produced when GSH reduces reactive oxygen species. Intracellular concentrations often reach millimolar levels, whereas plasma concentrations are much lower, typically in the low micromolar range. This gradient reflects active synthesis, transport, and consumption rather than passive distribution.
Synthesis occurs in two ATP-dependent steps: glutamate-cysteine ligase joins glutamate and cysteine to form gamma-glutamylcysteine, and glutathione synthetase adds glycine to complete the tripeptide. The pathway is feedback-inhibited by GSH and limited by cysteine availability, so cysteine supply often constrains production. Once formed, GSH participates in redox buffering, xenobiotic conjugation, and protein glutathionylation. Glutathione peroxidase uses GSH to reduce hydrogen peroxide and lipid peroxides, yielding GSSG, while glutathione reductase regenerates GSH using NADPH. Glutathione S-transferases conjugate electrophiles to GSH, supporting detoxification and excretion.
Because GSH is central to redox balance, its status is studied in aging, liver disease, neurodegenerative conditions, and metabolic disorders. Observational studies often report lower GSH or higher GSSG in affected tissues, but such associations do not establish that raising glutathione changes disease outcomes. Oral glutathione is digested into amino acids, and whether intact absorption occurs remains debated; precursors such as N-acetylcysteine and cysteine donors are also investigated. Regulatory agencies generally treat glutathione as a dietary supplement, not an approved drug, and clinical claims require evidence from controlled trials.
Several techniques are used for quantification. Enzymatic recycling assays rely on glutathione reductase and a colorimetric or fluorescent readout, offering sensitivity for total glutathione. High-performance liquid chromatography can separate GSH from GSSG and other thiols, often with UV, fluorescence, or electrochemical detection. Mass spectrometry provides structural confirmation and can quantify low-abundance species when paired with separation. Each approach has trade-offs in specificity, throughput, and equipment requirements, so method selection depends on the research question and available instrumentation.
Stability depends on pH, temperature, oxygen exposure, and trace metals. Aqueous solutions of reduced glutathione are susceptible to oxidation, especially when neutral or alkaline and exposed to air. Transition metal ions can catalyze thiol oxidation, so chelators and inert atmospheres are sometimes used in research settings. Standards are typically stored cold and desiccated, with limited freeze-thaw cycles. Questions remain about how closely in vitro stability data reflect the behavior of glutathione within intact cells and tissues.
Glutathione is a small tripeptide built from glutamate, cysteine, and glycine. The peptide bond between glutamate and cysteine uses the gamma-carboxyl group, a linkage that resists ordinary peptidases. Cells make it in two ATP-dependent steps: gamma-glutamylcysteine synthetase joins glutamate and cysteine, then glutathione synthetase adds glycine. The pathway is feedback-inhibited by glutathione itself, so intracellular levels tend to stay within a narrow range. Because cysteine is often limiting, sulfur amino acid supply influences how much glutathione a cell can produce.
In its reduced form, glutathione carries a sulfhydryl group that can donate electrons. This property lets it act as a major cellular antioxidant and redox buffer. Glutathione peroxidase uses it to reduce hydrogen peroxide and lipid peroxides, while glutathione reductase regenerates the reduced form using NADPH. The ratio of reduced glutathione to glutathione disulfide is widely used as an indicator of oxidative stress, though the ratio changes with compartment, cell type, and sample handling. Oxidized glutathione can also form mixed disulfides with proteins, affecting their activity.
Glutathione supports detoxification by conjugating reactive electrophiles through glutathione S-transferases. The resulting conjugates are processed and exported, often after further metabolism. It also stores cysteine, transports amino acids across membranes through the gamma-glutamyl cycle, and assists in the maturation of iron-sulfur clusters and some prostaglandins. In plants, animals, and many microbes, the molecule appears in similar roles, but concentrations vary enormously between tissues. Liver, kidney, and red blood cells tend to contain high amounts, while blood plasma contains much less.
Quantification of glutathione in biological or food samples commonly uses liquid chromatography coupled to ultraviolet, fluorescence, electrochemical, or mass spectrometric detection. Because the thiol group oxidizes readily, samples are often acidified or derivatized immediately after collection to stabilize reduced glutathione. Enzymatic recycling assays and colorimetric kits offer higher throughput but generally lower specificity than chromatographic methods. Mass spectrometry can distinguish glutathione from related thiols and allow simultaneous measurement of oxidized forms. Reported concentrations depend strongly on sample type, extraction procedure, and analytical platform.
Glutathione reference materials are sensitive to oxygen, light, and elevated temperature. Solid material is typically stored desiccated at -20 °C or below, while solutions require tighter control because thiol oxidation proceeds faster in liquid form. Aqueous solutions are often prepared fresh, kept cold, and protected from air; some protocols add acid or chelating agents to slow metal-catalyzed oxidation. Repeated freeze-thaw cycles can accelerate degradation and should be avoided. Stability data vary by matrix, so laboratories usually verify performance with their own storage conditions.
Quality control for glutathione measurements includes calibration with authenticated standards, internal standards where available, blank correction, and spike recovery checks. Because glutathione can form during sample processing or degrade before analysis, pre-analytical handling is a major source of variability. Interlaboratory comparisons often show differences in reported values due to method-specific calibration and detection principles. Interpretive thresholds are context-dependent, and no single reference range applies across all tissues or matrices. Researchers generally report both reduced and oxidized forms, along with the method and sample handling details.
Prolactin is available commercially for use in other animals, but not in humans. It is used to stimulate lactation in animals. The biological half-life of prolactin in humans is around 15–20 minutes. The D2 receptor is involved in the regulation of prolactin secretion, and agonists of the receptor such as bromocriptine and cabergoline decrease prolactin levels while antagonists of the receptor such as domperidone, metoclopramide, haloperidol, risperidone, and sulpiride increase prolactin levels. D2 receptor antagonists like domperidone, metoclopramide, and sulpiride are used as galactogogues to increase prolactin secretion in the pituitary gland and induce lactation in humans. Breast-feeding Breastfeeding and fertility Epileptic seizure Hyperprolactinaemia Hypothalamic–pituitary–prolactin axis Male lactation Prolactin modulator Prolactin receptor Prolactin-releasing hormone Prolactinoma Weaning MedlinePlus Encyclopedia: Prolactin Overview of all the structural information available in the PDB for UniProt: P01236 (Prolactin) at the PDBe-KB.
2 Bh + 3 O2 + 2 HCl → 2 BhO3Cl + H2 The longer-lived heavy isotopes of bohrium, produced as the daughters of heavier elements, offer advantages for future radiochemical experiments. Although the heavy isotope 274Bh requires a rare and highly radioactive berkelium target for its production, the isotopes 272Bh, 271Bh, and 270Bh can be readily produced as daughters of more easily produced moscovium and nihonium isotopes.
=== Canine osteoarthritis === CBD's ability to help regulate the endocannabinoid system and reduce the release of excitatory neurotransmitters could result in a retrograde inhibitory signal that lessens chronic pain responses. Studies in dogs with chronic pain associated with osteoarthritis showed an increase in level of activity in animals receiving CBD-rich food supplements.
Sources: en.wikipedia.org
for molecular models that are more realistic than rigid elastic spheres, such as those incorporating intermolecular attractions. Doing so is necessary to reproduce the correct temperature dependence of
=== Foreign political and diplomatic figures === Henry Cruger* (1758), member of the Parliament of Great Britain 1774–1790 and the New York State Senate Isaac Wilkins (1760), judge, member of the Nova Scotia House of Assembly Thomas Henry Barclay (1772), United Empire Loyalist; member of the 6th General Assembly of Nova Scotia Tang Shaoyi* (1882), first premier of the Republic of China William Sanford Evans (1895), Manitoba politician, mayor of Winnipeg 1909–1911 Pixley ka Isaka Seme (1906), founder and president of the African National Congress Wellington Koo (1909), president of the Republic of China and China's ambassador to the United States; Chinese delegate to the Paris Peace Conference, 1919 and the League of Nations; judge on the International Court of Justice 1957–1967 Jun Ke Choy (1915), former mayor of Hangzhou, chairman of China Merchants Group, and founder of the Chinese Culture Center Yu Tsune-chi (1922), Chinese ambassador to Italy and Spain, delegate to the San Francisco Conference, United Nations and the International Labour Organization Mario Laserna Pinzón (1948), Colombian diplomat and educator; founded the Universidad de Los Andes Colin Hughes (1949), first commissioner of the Australian Electoral Commission Uldis-Ivars Grava (1958), Latvian parliamentarian, former director of Latvijas Televīzija and chairman of American Latvian Association Johan Jorgen Holst (1960), Norwegian minister of Defence and Foreign Affairs; heavily involved with the Oslo Accords Yossi Alpher (1964), former Mossad officer and director of the Jaffee Center for Strategic Studies at Tel Aviv University Dore Gold (1975), Israeli political advisor and diplomat; former ambassador to the United States Toomas Hendrik Ilves (1975), president of Estonia Carson Wen (1975), three-time Hong Kong deputy to the National People's Congress and former vice chairman of the Democratic Alliance for the Betterment and Progress of Hong Kong Geoffrey Onyeama (1977), Nigerian minister of Foreign Affairs since 2015, son of Nigerian justice Charles Onyeama Michael Oren (1977), Israeli historian and former Israeli ambassador to the United States Miloon Kothari (1979), United Nations special rapporteur on adequate housing Kim Hyun-jong (1981), former South Korean minister of Trade and Special Advisor to President Moon Jae-in Ken Ofori-Atta (1984), Ghanaian economist and investment banker and current minister for Finance and Economic Planning, member of the Ofori-Atta family Akiva Tor (1985), Israeli ambassador to South Korea Abdullah bin Khalid bin Sultan Al Saud (2010), Saudi Arabia's permanent representative to the United Nations in Vienna, ambassador to Austria, Slovakia and Slovenia, great-grandson of Ibn Saud
=== Oak Park River Forest High School Outbreak === After 17 new cases were diagnosed in one week, the Oak Park Health Department forced Oak Park River Forest High School to cancel all extracurricular activities on December 3, 2021 and hinted toward a future move to suspend in-person learning. Oak Park Public Health Director Dr. Theresa Chapple expressed concerns that "only about 100 to 200 students" were tested each week which left the department blind to the actual size of the outbreak. SHIELD Illinois was engaged by the district on Saturday, December 4 about the possibility of testing the entire school population in one day. SHIELD rallied every employee trained to collect specimens, including executive leadership, accounting specialists, and logistics team members. Monday, December 6, 2021, SHIELD Illinois collected specimens from 1,651 students, faculty, and staff. This initial round of testing identified 20 positive patients. The health department allowed extracurricular activities to resume on December 7, 2021. SHIELD Illinois repeated the same process on December 9. This time testing 1,396 faculty, staff, and students--identifying an additional 3 positive cases.
Sources: en.wikipedia.org
Glutathione is built from three amino acids: glutamate, cysteine, and glycine. The linkage involves the gamma-carboxyl group of glutamate rather than the alpha-carboxyl group, which is unusual for peptides. This structure protects the bond from some common peptidases.
It is present in nearly all cells, with notable amounts in the liver, kidneys, and red blood cells. The highest intracellular concentrations are usually in the millimolar range. Levels differ by tissue, age, and physiological state.
It is not classified as an essential nutrient because cells can synthesize it from amino acids. Dietary sources exist, but their contribution to tissue pools is not fully established. The body's production depends on enzyme activity and precursor availability.
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.