A practical reference on glutathione: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-06-06 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C10H17N3O6S | Refers to the reduced form |
| Molar mass | 307.32 g/mol | Calculated for the neutral molecule |
| Appearance | White crystalline powder | Often hygroscopic; protect from moisture |
| Water solubility | Soluble in water | Reported values vary with purity and form |
| Alternative names | GSH, reduced glutathione | GSH specifies the thiol form |
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.
Cells synthesize glutathione through two ATP-dependent steps: glutamate-cysteine ligase joins glutamate and cysteine, and glutathione synthetase adds glycine to form the complete tripeptide. Breakdown occurs through gamma-glutamyl transpeptidase and subsequent peptidase reactions, forming the gamma-glutamyl cycle. Within cells, glutathione also forms a disulfide-linked dimer called GSSG when two GSH molecules react. The balance between GSH and GSSG is widely used as an indicator of oxidative conditions, although the ratio can vary by compartment and tissue.
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.
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.
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. 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.
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.
=== Freeze drying (lyophilized) === Donkey milk can be freeze-dried to preserve the biological quality of the milk, and so preserve its nutritional, functional, and cosmetic properties. This is possible because in freeze drying the milk is frozen and brought under vacuum at low temperatures. During this process, the water is removed by sublimation. The result is approximately ten percent of dry matter that is called lyophilized (or freeze-dried) donkey milk. This powder is easy to reconstitute. The lyophilized product has to be packaged without any oxygen. It has a shelf life of two years. Normally it is produced from pasteurized donkey milk so it is ready to use. Analysis of freeze-dried donkey's milk has demonstrated that the natural colour, flavours, nutrients, and bioactive substances of fresh donkey milk are retained. Spray-drying is another way to dry products, in which the milk is heated and vitamins and other important bioactive substances may get lost. In contrast, Freeze-drying does not require chemical preservatives and can be either consumed directly or re-hydrated easily. However, this method for is costly, and is practiced only by a few companies. This product is easy to find in Italy, where it was for the first time put on the market.
=== Sri Lankan === Soy sauce (Sinhala: සෝයා සෝස්) is a popular food product used in Sri Lanka and is a major ingredient used in the nationally popular street food dish kottu. Soy sauce has largely been produced by the Sri Lankan Chinese community but its production has also spread to other communities in Sri Lanka. Soy sauce production in Sri Lanka is the same as the production of soy sauce in Indonesia. Fermentation occurs over a period of three months. The soy beans which are steeped in brine are then pressed to obtain a liquid sauce.
Throughout 1948 and 1949, the Việt Minh engaged in ambushes and sabotage of French convoys and infrastructure. Meanwhile, the French government was still looking for a political solution and major military operations stalled for a lack of manpower. With the triumph of the communists in China's civil war in October 1949, the Vietnamese communists gained a major political ally on their northern border, who supported them with advisers, weapons and supplies along with camps where new recruits were trained. Between 1950 and 1951, Giap re-organized his local forces into five full conventional infantry divisions, the 304th, 308th, 312th, 316th and the 320th. In January 1950, Ho's government gained recognition from China and the Soviet Union. Shortly after in February, the government of Bảo Đại gained recognition by the United States and the United Kingdom. Along with Mao Zedong's victory in China, this gesture by the main Communist powers, played a part in shifting the US view of the war, which began to be seen as part of the global struggle against Communism. Starting in May, the United States began to provide military aid to France in the form of weaponry and military observers. In June 1950, the Korean War broke out between communist North Korea (DPRK) supported by China and the Soviet Union, and South Korea (ROK) supported by the United States and its allies in the UN. The Cold War was turning 'hot' in East Asia, and the American government feared communist domination of the entire region would have deep implications for American interests.
Sources: en.wikipedia.org
=== Colorado === On May 17, 2024, Colorado Governor Jared Polis signed the Colorado AI Act (CAIA) into law. The CAIA establishes requirements for deployers and developers of high-risk AI systems, including transparency obligations and risk assessments, to prevent algorithmic discrimination against Colorado residents. It is the first comprehensive, state-level law that regulates high-risk AI systems in the United States. The law was unpopular among pro-business advocates. An attempt to amend the regulation failed, but its implementation was delayed from the original February 1, 2026 start date to an expected June 1, 2026 start. Jared Polis has created a committee to investigate its implementation. Brianna Titone, the bill's sponsor, criticized the commission for being full of industry representatives without representation from consumers across the state. On May 14, 2026, Polis signed into law SB 26-189, which repealed and replaced CAIA. The replacement law eliminated the focus on high-risk systems; instead, it requires companies that deploy AI for decision-making related to certain topics (like employment or housing) to inform individuals that AI is being used.
== Research == Eberlin developed a pen-like device, called the "MasSpec Pen" or "The Cancer Pen", that has demonstrated the capability to detect cancerous tissue by delivering a discrete water droplet to extract biomolecules from the tissue's surface and transporting them to a mass spectrometer for molecular analysis. The pen allows surgeons to achieve a better understanding of which tissues should be removed. As a co-principal investigator at the University of Texas at Austin, Eberlin has developed a method to detect thyroid cancer using Desorption electrospray ionization mass spectrometry (DESI-MS) imaging of fine-needle aspiration biopsies. It is two-thirds more accurate than the test already in use, fine-needle aspiration, which yields more indeterminate results when used in isolation. In addition to her work on cancer diagnosis, Eberlin has also worked with Cooks and her father on the use of mass spectrometry to quickly detect counterfeit money. Eberlin is concerned about the representation of women and diversity in science. In interviews, she has stressed the importance of women in higher levels of academia as well as leadership.
Analysts disagree as to whether a period of global tension analogous to the Cold War is possible in the future, while others, like Carnegie Moscow Center director Dmitri Trenin, used the term to describe the ongoing renewed tensions and hostilities that rose dramatically in 2014 between Russia and the West. Some political analysts argue that Russia's 2014 annexation of Crimea, which started the Russo-Ukrainian war, marked the beginning of a new Cold War between Russia and the West or NATO. By August 2014, both sides had implemented economic, financial, and diplomatic sanctions upon each other: virtually all Western countries, led by the US and European Union, imposed punitive measures on Russia, which introduced retaliatory measures. In 2014, notable figures such as Mikhail Gorbachev warned, against the backdrop of a confrontation between Russia and the West over the Russo-Ukrainian War, that the world was on the brink of a new cold war, or that it was already occurring. The American political scientist Robert Legvold also believes a new cold war between Russia and the West started in 2014 when Russia annexed Crimea and supported an insurgency in eastern Ukraine. Ian Bremmer, president of the Eurasia Group, argued that the Ukraine conflict did not fit his definition of a cold war. Stephen F. Cohen, Robert D. Crane, and Alex Vatanka, among others, have all referred to a "US–Russian Cold War".
Sources: en.wikipedia.org
=== Pharmacokinetics === Both nicotinic acid and nicotinamide are rapidly absorbed from the stomach and small intestine. Absorption is facilitated by sodium-dependent diffusion, and at higher intakes, via passive diffusion. Unlike some other vitamins, the percent absorbed does not decrease with increasing dose, so that even at amounts of 3-4 grams, absorption is nearly complete. With a one gram dose, peak plasma concentrations of 15 to 30 μg/mL are reached within 30 to 60 minutes. Approximately 88% of an oral pharmacologic dose is eliminated by the kidneys as unchanged nicotinic acid or nicotinuric acid, its primary metabolite. The plasma elimination half-life of nicotinic acid ranges from 20 to 45 minutes. Nicotinic acid and nicotinamide are both converted into the coenzyme NAD. NAD converts to NADP by phosphorylation in the presence of the enzyme NAD+ kinase. High energy requirements (brain) or high turnover rate (gut, skin) organs are usually the most susceptible to their deficiency. In the liver, nicotinamide is converted to storage nicotinamide adenine dinucleotide (NAD). As needed, liver NAD is hydrolyzed to nicotinamide and nicotinic acid for transport to tissues, there reconverted to NAD to serve as an enzyme cofactor. Excess nicotinic acid is methylated in the liver to N1-methylnicotinamide (NMN) and excreted in urine as such or as the oxidized metabolites N1-methyl-2-pyridone-5-carboxamide and N1-Methyl-4-pyridone-3-carboxamide (2PY and 4PY). Decreased urinary content of these metabolites is a measure of niacin deficiency.
== Demographics == In the United States, a 2023 Gallup poll found that 4% of adults identified as vegetarian and 1% as vegan, little changed from 2012 and 2018 but slightly lower than the 6% who identified as vegetarian in 1999 and 2001. Prejudice researcher Gordon Hodson argues that vegetarians and vegans frequently face discrimination where eating meat is held as a cultural norm.
However, this can be possible: for example, inhibitors based on the compounds mycophenolic acid and tiazofurin inhibit IMP dehydrogenase at the NAD+ binding site. Because of the importance of this enzyme in purine metabolism, these compounds may be useful as anti-cancer, anti-viral, or immunosuppressive drugs. Other drugs are not enzyme inhibitors, but instead activate enzymes involved in NAD+ metabolism. Sirtuins are a particularly interesting target for such drugs, since activation of these NAD-dependent deacetylases extends lifespan in some animal models. Compounds such as resveratrol increase the activity of these enzymes, which may be important in their ability to delay aging in both vertebrate, and invertebrate model organisms. In one experiment, mice given NAD for one week had improved nuclear-mitochrondrial communication. Because of the differences in the metabolic pathways of NAD+ biosynthesis between organisms, such as between bacteria and humans, this area of metabolism is a promising area for the development of new antibiotics. For example, the enzyme nicotinamidase, which converts nicotinamide to nicotinic acid, is a target for drug design because this enzyme is absent in humans but present in yeast and bacteria. In bacteriology, NAD, sometimes referred to factor V, is used as a supplement to culture media for some fastidious bacteria. High-cost unlicensed infusions of NAD+ have been claimed in the UK to be "clinically proven" and "effective" treatment for alcoholism and drug abuse.
== Reactions == The cycle comprises three enzyme-catalysed reactions. The first stage is the deamination of the purine nucleotide adenosine monophosphate (AMP) to form inosine monophosphate (IMP), catalysed by the enzyme AMP deaminase:
Sources: en.wikipedia.org
It is a tripeptide of glutamate, cysteine, and glycine. The glutamate-cysteine bond is unusual because it forms through the gamma-carboxyl group.
It reflects the balance between oxidant exposure and antioxidant capacity. The ratio is not a direct clinical diagnosis and depends on the tissue and sample method.
No. It also participates in detoxification, amino acid transport, and protein modification. Its roles vary by cell type and compartment.
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.