The short version of reduced glutathione fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-04-30 and is reviewed periodically as new material appears.
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.
Quality control for glutathione materials checks identity, assay, purity, water content, and disulfide content. Commercial products vary from research-grade powder to dietary supplements, and labels may not distinguish reduced from oxidized forms. In the United States, oral glutathione is commonly sold as a dietary supplement rather than an approved drug, while injectable forms fall under different rules and may require a prescription. Regulatory status differs by country. Analytical certificates, when available, help verify what a material contains, but independent testing remains important for interpretation.
Laboratory measurement of glutathione typically starts with rapid acid extraction to prevent oxidation and enzymatic degradation. Common methods include enzymatic recycling assays, high-performance liquid chromatography, and liquid chromatography coupled with mass spectrometry. The recycling assay uses glutathione reductase and a thiol-reactive colorimetric or fluorescent reagent, measuring total glutathione after converting disulfide forms. Chromatographic methods can separate reduced and oxidized forms, which helps when the redox ratio is the target. Choice of method affects sensitivity, specificity, and the amount of sample needed.
Samples for glutathione analysis require careful handling because the compound oxidizes readily and can be consumed by enzymes after collection. Blood is often treated with acid or thiol-blocking agents soon after draw, and plasma should be separated quickly from red blood cells. Tissues are usually snap-frozen or extracted immediately. Aqueous solutions of glutathione are less stable than dry powder and degrade faster at neutral or alkaline pH, in light, or with dissolved oxygen. Repeated freeze-thaw cycles also reduce reliability.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C10H17N3O6S | For reduced glutathione; the oxidized dimer has two sulfur atoms. |
| Molar mass | 307.32 g/mol | Calculated for the reduced form. |
| Appearance | White to off-white crystalline powder | Typical for solid reagent; solutions are usually colorless. |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar organic solvents. |
| Typical storage | -20 °C, desiccated, protected from light | Limits oxidation, moisture uptake, and degradation. |
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.
Quality control for glutathione focuses on identity, purity, and oxidation state. Certificates of analysis may report assay value, water content, and the presence of GSSG or other impurities. Chromatographic purity is often expressed as a percentage of peak area. Reference standards help laboratories compare results across instruments and batches. Because glutathione is a small, polar molecule, separation from cysteine, gamma-glutamylcysteine, and related thiols can be challenging. Verification often combines more than one analytical technique.
Measuring glutathione requires attention to sample preparation because the molecule oxidizes readily. Blood, tissue, and cell samples are often treated with acid to precipitate proteins and stabilize the thiol. Without such steps, GSH can convert to GSSG or form mixed disulfides during storage. Analytical methods include spectrophotometric assays, high-performance liquid chromatography, and mass spectrometry. Each approach has different sensitivity, specificity, and susceptibility to interference from related compounds in complex matrices.
Biosynthesis proceeds in two ATP-dependent steps. First, glutamate-cysteine ligase joins glutamate and cysteine. Second, glutathione synthetase adds glycine to the intermediate. The pathway is regulated by cysteine availability, enzyme expression, and feedback inhibition by glutathione itself. Liver tissue has a particularly high capacity for synthesis and export. Because the molecule is made inside cells, circulating glutathione reflects a balance of release, uptake, and breakdown rather than simple dietary supply.
Functionally, glutathione supports redox balance by donating electrons and becoming oxidized. It also serves as a cofactor for enzymes such as glutathione peroxidases and glutathione S-transferases. These enzymes participate in peroxide reduction and in conjugation reactions that help process reactive molecules. Separate from antioxidant roles, glutathione can modify protein cysteines through S-glutathionylation, influencing enzyme activity and signaling. Research continues to examine how these chemical roles translate into whole-organism effects.
A type of study in which the patients (single-blinded) or the patients and their doctors (double-blinded) do not know which drug or treatment is being given. The opposite of a blinded study is an open label study. (NCI)
== Research == Antibodies and antigens, produced in the Human Protein Atlas workflow, are used in research projects to study potential biomarkers in various diseases, such as breast cancer, prostate cancer, colon cancer, diabetes, autoimmune diseases, ovarian cancer and renal failure. Researchers involved with Human Protein Atlas projects, are sharing protocols and method details in an open-access group on protocols.io. A large effort is put into validating the antibody reagents used for profiling of tissues and cells, and the HPA has implemented stringent antibody validation criteria as suggested by the International Working Group for Antibody Validation (IWGAV).
Malabar had been traditionally used to denote the west coast of Southern India that forms the present-day state of Kerala and adjoining areas. The word mala or malaya means "mountain" in the Tamil and Malayalam languages, as also in Sanskrit. The word "malabathrum" is thought to have been derived from the Sanskrit tamālapattram (तमालपत्त्रम्), literally meaning "dark-tree leaves".
For services to Seriously and Terminally Ill Children and their Families. Kevin Shakesheff. Co-Founder, High Tide Foundation and President, Institute of Chartered Shipbrokers and Educational Fund. For services to Young People in Business and to the Maritime Industry. Ian James Donald Sharp. Lately Captain, 6th Wolverhampton Boys' Brigade. For services to Young People in Wolverhampton. Yassamin Sheel. National Lead, United Teaching, Greater Manchester. For services to Children. Karen Eileen Shepperson. Director of People and Operations, Ofsted. For services to Education. Savraj Singh Shetra. Field Intelligence Officer, Home Office. For Public Service. Dr. Hamsaraj Gundal Mahabala Shetty. Consultant Physician, University Hospital of Wales. For services to Stroke Services in Wales. David Alan Short, JP. Lately Group Technology Director, BAE Systems. For services to Military Capability. David Norman Short. For services to Pastoral Care and to the community in Buckinghamshire. John Stanley William Simpson. For services to Agriculture and to the community in Lewes, East Sussex. Margaret Ann Simpson. For services to the community in Oxfordshire. Roselind Pamela Sinclair. Lecturer in Design Education, Goldsmiths, University of London. For services to the Arts. Nirmal Singh. Chaplain, North West Prisons HM Prison and Probation Service. For services to Community Development and Interfaith Integration. Catherine Elizabeth Skidmore. Head of Aviation Resilience, Department for Transport. For services to Major Event Responses. Christopher Jon Smith.
=== Macroscopic examination === Visual examination of the specimen may provide information to the pathologist or the physician. For example, fluid drained from an abscess may appear cloudy, or cerebrospinal fluid obtained by lumbar puncture may exhibit xanthochromia, suggesting a bleed has occurred. Laboratory technologists may provide qualitative descriptions accordingly.
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Chemical data, Clinical data and Molecular biology/biochemistry data. The database contains 220,945 metabolite entries including both water-soluble and lipid soluble metabolites. Additionally, 8,610 protein sequences (enzymes and transporters) are linked to these metabolite entries. Each MetaboCard entry contains 130 data fields with 2/3 of the information being devoted to chemical/clinical data and the other 1/3 devoted to enzymatic or biochemical data. The version 3.5 of the HMDB contains >16,000 endogenous metabolites, >1,500 drugs and >22,000 food constituents or food metabolites. This information, available at the Human Metabolome Database and based on analysis of information available in the current scientific literature, is far from complete. In contrast, much more is known about the metabolomes of other organisms. For example, over 50,000 metabolites have been characterized from the plant kingdom, and many thousands of metabolites have been identified and/or characterized from single plants. Each type of cell and tissue has a unique metabolic 'fingerprint' that can elucidate organ or tissue-specific information. Bio-specimens used for metabolomics analysis include but not limit to plasma, serum, urine, saliva, feces, muscle, sweat, exhaled breath and gastrointestinal fluid. The ease of collection facilitates high temporal resolution, and because they are always at dynamic equilibrium with the body, they can describe the host as a whole.
Ho's extensive research achievements have garnered news coverage in The Economist, Forbes, Nature, CNN, NPR, as well as The Washington Post. He was also featured in the National Geographic Channel program, Known Universe. Most recently, the Augmented AI platform was featured by FuturizeX, a partnership between the X PRIZE Foundation and UCLA. Recent clinical advances using this AI approach to enhance clinical outcomes were recognized among the finalists for the SLAS Innovation Award, selection among the SLAS Technology 10, and featured at the PM3 panel at InnovFest Unbound. Ho currently serves as the Director of The N.1 Institute for Health (N.1), which was previously known as SINAPSE, as well as Director of the Institute for Digital Medicine (WisDM) at the Yong Loo Lin School of Medicine, National University of Singapore. N.1 and WisDM are clinical stage research institutes that harnesses AI and Digital Medicine for novel clinical trial designs for interventional studies. Over ten first-in-human clinical studies based on N.1 and WisDM-developed technologies are ongoing or nearing clearance for the start of prospective clinical studies. N.1 and WisDM have pioneered the development and subsequent clinical translation of platforms pertaining to N-of-1 medicine, digital therapeutics, COVID-19 therapeutic regimen optimization, pain management, cognitive neuroengineering, and novel drug development, among many others. Ho is an elected member of the US National Academy of Inventors (NAI).
Critical illness polyneuropathy (CIP) and critical illness myopathy (CIM) are overlapping syndromes of diffuse, symmetric, flaccid muscle weakness occurring in critically ill patients and involving all extremities and the diaphragm with relative sparing of the cranial nerves. CIP and CIM have similar symptoms and presentations and are often distinguished largely on the basis of specialized electrophysiologic testing or muscle and nerve biopsy. The causes of CIP and CIM are unknown, though they are thought to be a possible neurological manifestation of systemic inflammatory response syndrome. Corticosteroids and neuromuscular blocking agents, which are widely used in intensive care, may contribute to the development of CIP and CIM, as may elevations in blood sugar, which frequently occur in critically ill patients. CIP was first described by Charles F. Bolton in a series of five patients. Combined CIP and CIM was first described by Nicola Latronico in a series of 24 patients.
=== Other psychoactive infusions === Ayahuasca, a South American psychoactive decoction prepared from Banisteriopsis caapi vine and a dimethyltryptamine (DMT)-containing plant, which has different legal statuses depending on jurisdiction. Cannabis tea, which contains the psychoactive THC. It is a common drink in India, where it is known as bhang. Coca tea, infusion made from coca leaves. Contains trace amounts of cocaine and similar alkaloids. In some countries where coca is illegal, products marketed as "coca tea" are supposed to be decocainized, i.e., the pharmacologically active components have been removed from the leaf using the same chemicals as manufacturing cocaine. Kava root tea, common in Pacific island cultures (Polynesia, Melanesia, Micronesia), which has sedative effects and anesthetic effects caused by compounds called kavalactones. The traditional form is a water-based suspension of kava roots. Kratom tea made from the dried leaves of the kratom tree. It has opioid-like properties and some stimulant-like effects. St. John's wort tea, the plant has been shown to have antidepressant properties according to a 2017 meta-analysis. Ephedra tea, mainly from the plant Ephedra sinica. It contains the stimulant ephedrine. It has been used in traditional Chinese medicine, where it is called máhuáng, for more than 2,000 years. Ephedra tea was also used by Native Americans and Mormons, hence the name "Mormon tea" and "Indian tea". Poppy tea, brewed from the poppy straw or seeds of several species of poppy (most commonly Papaver somniferum).
Sources: en.wikipedia.org
GSH is the reduced form with a free thiol group, while GSSG is the oxidized disulfide-linked dimer. Most assays distinguish the two because their balance reflects redox conditions. The names are not interchangeable.
It is synthesized in the body from amino acids, so it is not classified as an essential dietary nutrient for most people. Dietary and supplemental forms are studied for their effects on tissue levels and health markers. Evidence varies by population and outcome.
The phrase highlights its high intracellular concentration and its role in several antioxidant and detoxification reactions. It is not the only antioxidant, and the term can oversimplify its functions. Scientific descriptions usually specify the pathway or enzyme involved.
Common approaches include enzymatic recycling assays, HPLC, and LC-MS/MS. Acid extraction and rapid processing limit oxidation before analysis.