What is glutathione?
Glutathione (GSH) is a tripeptide — a small molecule composed of three amino acids: glutamate, cysteine, and glycine — found in virtually every cell in the body. It serves as the primary intracellular antioxidant, directly neutralising free radicals and reactive oxygen species while also recycling other antioxidants such as vitamins C and E. This recycling ability is why it's often called the "master antioxidant."
Why it matters clinically
Glutathione plays central roles in four critical processes: antioxidant defence (protecting cells from oxidative damage), detoxification (conjugating and eliminating toxins, heavy metals, and drug metabolites), immune function (supporting lymphocyte activity and inflammatory regulation), and cellular signalling (modulating gene expression and apoptosis).
Declining glutathione levels have been associated with ageing, neurodegenerative diseases, liver disease, chronic infections, and many inflammatory conditions. For practitioners, measuring glutathione status provides a direct assessment of a patient's oxidative stress burden and antioxidant capacity.
Reduced vs oxidised: the ratio matters
Glutathione exists in two forms: reduced (GSH, the active antioxidant) and oxidised (GSSG, the spent form). The ratio of GSH to GSSG is a key indicator of cellular redox status. A healthy ratio is typically greater than 100:1. When oxidative stress overwhelms the cell's capacity to regenerate reduced glutathione, this ratio shifts — providing a measurable signal of cellular stress.
Masdiag's Glutathione Index reports both forms from a dried blood spot, giving practitioners actionable data on their patients' antioxidant reserve.
Who should consider testing?
Glutathione testing is particularly relevant for patients with chronic fatigue or unexplained inflammation, individuals exposed to environmental toxins or heavy metals, those with liver conditions, older adults concerned about age-related oxidative stress, and athletes or high-performers monitoring recovery and cellular stress.
Frequently asked questions
Can you test glutathione levels?
Yes. Masdiag measures both reduced (GSH) and oxidised (GSSG) glutathione from a dried blood spot using LC-MS/MS, allowing assessment of both total glutathione status and the GSH:GSSG ratio — a key indicator of cellular redox balance. Unlike supplements that claim to "raise" glutathione, testing provides objective evidence of your actual status.
What depletes glutathione?
Oxidative stress, chronic inflammation, infections, heavy metal exposure, intense exercise, chronic disease states (including cancer, autoimmune conditions, and neurodegeneration), certain medications (like acetaminophen), alcohol consumption, and poor sleep all deplete glutathione. Aging itself is associated with declining glutathione production, particularly in tissues with high energy demands.
Can you take glutathione supplements?
Oral glutathione is largely broken down in the digestive system, making supplementation ineffective for raising intracellular levels. More effective approaches include precursor supplementation (N-acetylcysteine, lipoic acid, or milk thistle), optimising nutritional cofactors (selenium, zinc, vitamins C and E), managing oxidative stress through diet and exercise, and treating underlying inflammatory or infectious conditions that deplete glutathione.
Explore This Test
View the full method details, sample requirements, and analyte panel for our Glutathione Index test.
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