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 2026-03-24. Where a claim depends on a specific study, the study is described rather than over-claimed.
Glutathione supports several cellular processes beyond direct antioxidant action. It serves as a cofactor for glutathione peroxidase and glutathione S-transferase enzymes, which reduce peroxides and conjugate electrophiles, respectively. The molecule also acts as a reservoir of cysteine, an amino acid that can limit protein synthesis and redox signaling. In human nutrition, oral glutathione is sold as a supplement, but how much intact glutathione reaches tissues after ingestion remains an active research question. Clinical claims about supplementation are not uniformly supported by controlled trials.
Glutathione is a small tripeptide built from glutamic acid, cysteine, and glycine. Its peptide bond between glutamate and cysteine involves the gamma-carboxyl group rather than the usual alpha-carboxyl group. This structure gives the molecule a reactive thiol on the cysteine residue. The reduced form, often abbreviated GSH, is the predominant intracellular species in many cell types. Because the thiol can donate electrons, glutathione participates in redox chemistry and in the conjugation of reactive molecules.
In cells, glutathione exists mainly in a reduced form called GSH. When two GSH molecules react, they form oxidized glutathione, or GSSG, which contains a disulfide bond. The ratio of GSH to GSSG is often used as an indicator of oxidative stress. Enzymes such as glutathione peroxidase and glutathione reductase help cycle the molecule between these two states. This cycling supports antioxidant defense, detoxification of reactive molecules, and regulation of certain signaling pathways.
Glutathione is present in most tissues, with especially high concentrations in the liver. It also serves as a cofactor for some enzymes and helps transport amino acids across cell membranes. In plants and microorganisms, glutathione contributes to stress responses and metal handling. The molecule is synthesized in two ATP-dependent steps, first producing gamma-glutamylcysteine and then adding glycine. Because cysteine availability often limits synthesis, dietary and metabolic factors can influence glutathione levels. Research continues to examine how these levels relate to health and disease.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. The peptide bond between glutamate and cysteine uses the gamma-carboxyl group of glutamate rather than the alpha-carboxyl group. This unusual linkage protects the molecule from many common peptidases. The cysteine side chain carries a thiol group that can undergo reversible oxidation. Because of this thiol, glutathione participates in redox reactions and helps maintain the reducing environment inside most cells in living systems.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C10H17N3O6S | Reduced form; oxidized dimer is C20H32N6O12S2 |
| Molar mass | 307.32 g/mol | For reduced glutathione (GSH) |
| Appearance | White crystalline powder | Typical laboratory and supplement-grade material |
| Solubility | Soluble in water | Poorly soluble in ethanol and other nonpolar solvents |
| Typical storage | -20 C, desiccated, protected from light | Reduced form can oxidize in solution |
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.
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.
Interpreting glutathione measurements requires attention to pre-analytical variables. The GSSG concentration in a sample can rise artificially during storage or processing, making the GSH/GSSG ratio unreliable if not controlled. Reference ranges vary by specimen type, assay, and population, so comparisons across studies are difficult. Plasma glutathione is low and sensitive to hemolysis, while whole blood reflects primarily erythrocyte content. Many studies measure total glutathione rather than the reduced and oxidized forms separately, which limits conclusions about redox status.
Accurate measurement of glutathione begins with careful sample handling. Because GSH oxidizes rapidly to GSSG, samples must be processed quickly or frozen immediately. Acid precipitation with metaphosphoric acid or perchloric acid is common; it lowers pH, precipitates proteins, and helps preserve the reduced form. Chelating agents such as EDTA can limit metal-catalyzed oxidation. For whole blood, hemolysis releases glutathione from erythrocytes, so plasma and serum values differ substantially from whole blood values.
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 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.
== Cholesteric liquid crystals == Some cholesterol derivatives (among other simple cholesteric lipids) are known to generate the cholesteric liquid crystalline phase. The cholesteric phase is, in fact, a chiral nematic phase, and it changes color when its temperature changes. This makes cholesterol derivatives useful for indicating temperature in liquid-crystal thermometers and in temperature-sensitive paints.
In February 2023, Moore announced a $600 million, five-year partnership with the Baltimore Orioles to develop properties around Camden Yards. In September 2023, he and Orioles CEO John P. Angelos announced a memorandum of understanding that would extend the team's lease by 30 years, open development rights inside the park to private developers, and give the Orioles control over stadium operations and maintenance. The stadium lease was finalized in December 2023, but an agreement on the team's ground lease and redevelopment plan was postponed until 2027 following concerns from Senate President Bill Ferguson. Orioles CEO David Rubenstein later wrote in his book, Inside the Owner’s Box, that he wanted to focus on the roster and ongoing ballpark upgrades before pursuing real estate development around Camden Yards. In September 2026, Rubenstein engaged real estate firm Seregh to begin a "multiyear effort to try to redevelop the immediate area around Camden Yards". Moore supported keeping the Washington Commanders, who are contractually obligated to play at Northwest Stadium until September 2027, in Maryland. He initially said that he would not support spending state funds to keep the Commanders in Maryland, but later reiterated that he supported spending some taxpayer money on a new Commanders football stadium "if we know there's going to be a significant societal return on the investment". In November 2024, Moore opposed a federal bill to give Washington, D.C. greater control of the Robert F.
The UPMC Hillman Cancer Center, formerly titled the University of Pittsburgh Cancer Institute, is a National Cancer Institute designated cancer center and the flagship of the UPMC Cancer Centers network. Founded in 1985 at the University of Pittsburgh, the center is located in the Shadyside neighborhood of Pittsburgh and is connected to UPMC Shadyside via a pedestrian bridge.
==== Shortness of breath ==== Opioids may help with shortness of breath particularly in advanced diseases such as cancer and COPD. However, findings from two recent systematic reviews of the literature found that opioids were not necessarily more effective in treating shortness of breath in patients who have advanced cancer.
Sources: en.wikipedia.org
=== Center of Excellence for Transgender Health (UCSF) === The Center of Excellence for Transgender Health at the University of California, San Francisco was established in 2009, dedicated to improving health equity for trans and gender nonconforming communities. The Center of Excellence for Transgender Health is a national advisory board composed of transgender leaders from across the United States, bringing expertise in the research of transgender health. Guidelines for Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People contains guidelines developed by The Center of Excellence for Transgender Health that are widely used clinical guidelines for transgender healthcare.
Different conformations of PrPSc (often termed prion "strains") are thought to cause the distinct subtypes of prion disease, explaining variations in clinical features and progression. They are thought to affect signaling processes, damaging neurons and resulting in degeneration that causes the spongiform appearance in the affected brain. Other forms of TSEs that are found in humans are Gerstmann–Sträussler–Scheinker syndrome, fatal familial insomnia, kuru, and variably protease-sensitive prionopathy. Susceptibility and disease phenotype are influenced by a common polymorphism at codon 129 of the PRNP gene (methionine/valine). Notably, individuals homozygous at codon 129 are over-represented in sporadic CJD cases and tend to have shorter incubation periods.
"Cheese" is a heroin-based recreational drug that came to the attention of the media inside and outside the United States after a string of deaths among adolescents in Dallas, between 2005 and 2007. As of 2012 the drug use was now among older people who were teenagers around the period the drug was first discovered. Cheese is a combination of drugs, made by combining heroin with crushed tablets of certain over-the-counter cold medication, such as Tylenol PM. Such cold medications contain acetaminophen (paracetamol), the active ingredient in Tylenol, and the antihistamine diphenhydramine, the active ingredient in Benadryl. Cheese samples obtained in north Dallas contained between 2% and 8% heroin, in contrast to the 30% commonly found in black tar heroin. Users commonly take the powder by insufflation ("snorting") rather than by intravenous injection. This mixture is also known as "Tylenol With Smack", by analogy to the Tylenol With Codeine series. Due to the high concentrations of non-opiate substances relative to the diamorphine content of the drug, abuse and overdose of cheese are more dangerous than pure-form opiate overdoses. Emergency personnel must address the overdose effects of each component of the drug, since the contents and concentrations of each component vary widely among batches they must wait for either the completion of the toxicology report to begin treatment or wait for the effects of each drugs overdose to manifest. The acetaminophen content of the drug induces severe, irreversible damage to the liver when taken in high doses for long periods of time.
Depolarizing neuromuscular blockers: Depolarizing agents act as agonists for acetylcholine receptors. Succinylcholine is currently the only depolarizing neuromuscular blocking drug that has been placed in ongoing clinical use. Its pharmacological structure resembles two acetylcholine molecules combined through acetate methyl groups. It contains two quaternary ammonium radicals which associate with the two alpha subunits of the nicotinic receptor to cause depolarization. These nicotinic receptors respond to acetylcholine and are located in the central and peripheral nervous system, muscle, and other tissue. They act as the primary receptor in muscle for motor nerve-muscle communication which signals muscle contractions. Under normal conditions, without the interference of depolarizing neuromuscular blockers, when depolarization is triggered, voltage-gated sodium channels are activated due to sensing the depolarization from the activation of acetylcholine receptors. This causes the rapid opening of the sodium channels, then closure after a brief period, becoming inactivated. The membrane potential is then required to be reset before the reactivation of the sodium channels. This process occurs almost instantly with acetylcholine, within one ms, as it is rapidly hydrolyzed through acetylcholinesterase. However, when depolarizing neuromuscular blockers are applied, the modified structure of succinylcholine cannot be hydrolyzed by acetylcholinesterase.
==== Oxyhemoglobin ==== Oxyhemoglobin is formed during physiological respiration when oxygen binds to the heme component of the protein hemoglobin in red blood cells. This process occurs in the pulmonary capillaries adjacent to the alveoli of the lungs. The oxygen then travels through the blood stream to be dropped off at cells where it is utilized as a terminal electron acceptor in the production of ATP by the process of oxidative phosphorylation. It does not, however, help to counteract a decrease in blood pH. Ventilation, or breathing, may reverse this condition by removal of carbon dioxide, thus causing a shift up in pH. Hemoglobin exists in two forms, a taut (tense) form (T) and a relaxed form (R). Various factors such as low pH, high CO2 and high 2,3 BPG at the level of the tissues favor the taut form, which has low oxygen affinity and releases oxygen in the tissues. Conversely, a high pH, low CO2, or low 2,3 BPG favors the relaxed form, which can better bind oxygen. The partial pressure of the system also affects O2 affinity where, at high partial pressures of oxygen (such as those present in the alveoli), the relaxed (high affinity, R) state is favoured. Inversely, at low partial pressures (such as those present in respiring tissues), the (low affinity, T) tense state is favoured. Additionally, the binding of oxygen to the iron(II) heme pulls the iron into the plane of the porphyrin ring, causing a slight conformational shift. The shift encourages oxygen to bind to the three remaining heme units within hemoglobin (thus, oxygen binding is cooperative).
Sources: en.wikipedia.org
It is a tripeptide of glutamic acid, cysteine, and glycine. The linkage between glutamate and cysteine uses the gamma-carboxyl group, which is unusual for peptides.
GSH is the reduced form with a free thiol group. GSSG is the oxidized dimer formed when two GSH molecules join by a disulfide bond.
It is synthesized inside cells and is not classified as an essential dietary nutrient for most people. Dietary and supplemental sources are studied, but direct requirements are not established in the same way as for vitamins.
Glutathione is a tripeptide made from glutamate, cysteine, and glycine. Its cysteine residue provides a thiol group that is central to its redox activity. The glutamate-cysteine bond forms through the gamma-carboxyl group of glutamate.