Glutathione Research History: Discovery, Key Trials and Regulatory Timeline

Scope of This History Page

This page is for educational purposes only and is not medical advice; consult a licensed physician for any health question. It summarises what a verified set of indexed publications reported about glutathione, in the order those publications appeared. No dose, protocol or outcome is suggested here, and no claim appears without the PubMed link for the paper it came from.

One limitation is stated at the outset. The earliest isolation and naming reports for glutathione were published in the nineteenth and early twentieth centuries, long before PubMed indexing began, and none of those primary reports is part of the verified citation set used on this page. Rather than paraphrase dates and authors that cannot be linked, this history begins where the citable record begins: with modern reviews, method papers and mechanistic studies. Readers looking for the underlying biology rather than the chronology can start with the overview at PeptideU's glutathione learn page.

Discovery Themes in the Indexed Record

Because the original discovery papers sit outside the verified set, the indexed literature approaches discovery retrospectively, through review articles that narrate how glutathione-dependent systems were identified. A 2021 review in Redox Biology was framed explicitly around that kind of narrative, covering the discovery of glutaredoxin alongside its redox defence functions and additional roles (PMID 33932870). The study of glutaredoxin matters to glutathione history because glutaredoxins are glutathione-dependent oxidoreductases, and the review placed their identification within the broader development of redox biology (PMID 33932870).

A second retrospective thread concerns metabolism. For decades the γ-glutamyl cycle was the organising framework for glutathione synthesis and turnover, and a 2018 review in IUBMB Life revisited that framework under the title "The glutathione cycle: glutathione metabolism beyond the γ-glutamyl cycle" (PMID 29667297). Researchers writing that review positioned glutathione metabolism as broader than the classical cycle description (PMID 29667297). The catabolic half of the same question was addressed in a 2017 Antioxidants & Redox Signaling review titled "Glutathione Degradation", which focused specifically on how the tripeptide is broken down (PMID 28537416).

Chronological Timeline of the Cited Literature

2001: Glutathione Framed as a Disease-Associated Variable

The earliest entry in this citation set is a 2001 review in Current Opinion in Clinical Nutrition and Metabolic Care titled "Glutathione in disease", which surveyed the clinical literature linking glutathione status to disease states (PMID 11122562). That review is useful as a historical marker because it shows glutathione already being discussed in a clinical nutrition context at the start of the 2000s (PMID 11122562). The review did not establish a treatment protocol, and nothing in this page should be read as describing one.

2006: A Measurement Standard

Research history often turns on measurement rather than mechanism. In 2006, Nature Protocols published a step-by-step assay for the quantitative determination of glutathione and glutathione disulfide levels using the enzymatic recycling method (PMID 17406579). Researchers describing that protocol presented it as a route to quantifying both the reduced tripeptide and its disulfide form in biological samples (PMID 17406579). The availability of a standardised recycling assay is one reason the GSH/GSSG ratio became a widely reported laboratory variable in later work (PMID 17406579).

2017: Ferroptosis Reframes the Field

A 2017 paper in Nature Chemical Biology reported that oxidised arachidonic and adrenic phosphatidylethanolamines act as signals that navigate cells to ferroptosis (PMID 27842066). The study identified specific oxidised phospholipid species rather than bulk oxidation as the relevant death signal (PMID 27842066). This line of work is part of glutathione history because the glutathione-dependent enzyme glutathione peroxidase 4 restrains exactly the lipid peroxidation chemistry that the paper characterised (PMID 27842066).

The same year, the dedicated review "Glutathione Degradation" consolidated what was known about catabolic routes for the tripeptide (PMID 28537416). Taken together with the 2018 metabolism review, the two papers mark a period in which turnover, not only synthesis, became a focus (PMID 28537416, PMID 29667297).

2021-2022: Oncology Reviews and Comparative Biology

In 2021, Current Opinion in Biotechnology published a review on glutathione and its precursors in cancer, addressing how the tripeptide and the amino acids feeding its synthesis feature in tumour biology (PMID 33819793). The review is a research-history landmark rather than a clinical instruction, and it reported that glutathione and its precursors occupy a contested position in cancer research (PMID 33819793).

Comparative biology extended the record in 2022, when Biomedicines published a review of xenobiotic-metabolising enzymes in trematodes (PMID 36551794). Glutathione S-transferases fall within that enzyme class, and the review examined such detoxification systems in parasitic flatworms (PMID 36551794). A 2025 paper in Aquatic Toxicology continued the comparative thread by evaluating cnidarian models for toxicology research (PMID 40015151).

2024: Mitochondrial Glutathione Transport

Among the most recent mechanistic entries in this set, a 2024 Molecular Cell study reported dual regulation of the transporter SLC25A39 by the protease AFG3L2 and by iron, describing this as a control point for mitochondrial glutathione homeostasis (PMID 38157846). Researchers reported that SLC25A39 levels responded to both regulators rather than to a single input (PMID 38157846). A separate 2024 review in BBA Molecular Cell Research examined how mitochondria contribute to cytoplasmic iron-sulfur protein biogenesis, a pathway historically connected to glutathione-related sulfur chemistry (PMID 38641180).

Regulatory Timeline as Published

Regulatory history is the most frequently misstated part of glutathione's record, so the limits here are explicit. Within this verified citation set there is no paper documenting a marketing approval for glutathione itself as a drug product in any jurisdiction. The single regulatory milestone that can be cited is for a different sulfur-containing compound: Paediatric Drugs published "Sodium Thiosulfate: Pediatric First Approval" in 2023, documenting a first approval in a paediatric setting (PMID 36517667). That report concerned sodium thiosulfate, not glutathione, and it is included only because thiol and sulfur-donor chemistry is often discussed alongside glutathione (PMID 36517667).

Readers evaluating claims that glutathione was "approved" in a given year should note that the question of regulatory status differs by product form, by country and by whether a product is a drug, a dietary supplement, a cosmetic ingredient or a compounded preparation. None of those distinctions is resolved by the papers cited above, and this page does not assert a status that the verified literature does not document. This section is informational and is not legal advice.

Safety and Adverse Events: What Studies Report

The verified citation set for this page is composed of mechanistic studies, laboratory protocols and narrative reviews rather than controlled safety trials, so it contains no tabulated human adverse-event data. The 2001 clinical review discussed glutathione in the context of disease states rather than reporting an adverse-event profile for an administered product (PMID 11122562). The 2021 oncology review likewise addressed glutathione and its precursors as biological variables in cancer rather than as a characterised intervention with a published tolerability table (PMID 33819793). The one approval document in the set concerns sodium thiosulfate and not glutathione (PMID 36517667). The absence of adverse-event data in a citation set is not evidence of safety; it means the question was not the subject of these particular papers.

How to Read This Chronology

Three patterns stand out across the dated record. First, methodology preceded much of the mechanistic expansion, with the 2006 recycling assay protocol providing a shared way to quantify reduced and oxidised pools (PMID 17406579). Second, the field moved from describing glutathione as a general antioxidant to specifying compartments and transporters, illustrated by the 2024 report on SLC25A39 regulation in mitochondria (PMID 38157846). Third, cell-death biology supplied new context, as the 2017 ferroptosis paper linked defined oxidised phospholipids to a regulated death programme (PMID 27842066).

Reviews covering degradation and metabolism remain the practical entry points for anyone reconstructing the chronology, since both summarised decades of prior work in a single place (PMID 28537416, PMID 29667297). Nothing in this history establishes a human outcome, and no part of it should be read as guidance about using any product.

References

• Glutathione in disease (Current Opinion in Clinical Nutrition and Metabolic Care, 2001)
• Assay for quantitative determination of glutathione and glutathione disulfide levels using enzymatic recycling method (Nature Protocols, 2006)
• Oxidized arachidonic and adrenic PEs navigate cells to ferroptosis (Nature Chemical Biology, 2017)
• Glutathione Degradation (Antioxidants & Redox Signaling, 2017)
• The glutathione cycle: Glutathione metabolism beyond the γ-glutamyl cycle (IUBMB Life, 2018)
• Glutathione and its precursors in cancer (Current Opinion in Biotechnology, 2021)
• Glutaredoxin: Discovery, redox defense and much more (Redox Biology, 2021)
• Xenobiotic-Metabolizing Enzymes in Trematodes (Biomedicines, 2022)
• Sodium Thiosulfate: Pediatric First Approval (Paediatric Drugs, 2023)
• Dual regulation of SLC25A39 by AFG3L2 and iron controls mitochondrial glutathione homeostasis (Molecular Cell, 2024)
• Mitochondria function in cytoplasmic FeS protein biogenesis (Biochimica et Biophysica Acta. Molecular Cell Research, 2024)
• Cnidarian models for toxicology (Aquatic Toxicology, 2025)