Glutathione: Benefits, Dosage, Contraindications
Other name(s)
GSH
Scientific name(s)
L-Glutathione
Family or group:
Pseudovitamins
Indications
Rating methodology
EFSA approval.
Chemotherapy ✪✪✪✪✪
Glutathione protects cells against the toxicity of chemotherapy. A dose of 1.5 to 3 g/m² was administered by slow intravenous infusion over 15 to 20 minutes, immediately before chemotherapy.
Posologie
Oral route
1.5 - 3 g/m²
A pilot clinical trial of postoperative intensive weekly chemotherapy using cisplatin, epi-doxorubicin, 5-fluorouracil, 6S-leucovorin, glutathione, and filgrastim in patients with resected gastric cancer.
A phase II study of combination chemotherapy in advanced ovarian carcinoma with cisplatin and cyclophosphamide plus reduced glutathione as a potential protective agent against cisplatin toxicity.
High-dose cisplatin and cyclophosphamide with glutathione in the treatment of advanced ovarian cancer.
A randomized double-blind placebo-controlled clinical trial assessing the tolerability and efficacy of glutathione as an adjuvant to escalating doses of cisplatin in the treatment of advanced ovarian cancer.
Phase I trial of cisplatin in combination with glutathione.
Intensive weekly chemotherapy is not effective in advanced pancreatic cancer patients: a report from the Italian Group for the Study of Digestive Tract Cancer (GISCAD).
Influence of glutathione administration on the disposition of free and total platinum in patients after administration of cisplatin.
Intensive weekly chemotherapy for advanced gastric cancer using fluorouracil, cisplatin, epi-doxorubicin, 6S-leucovorin, glutathione, and filgrastim: a report from the Italian Group for the Study of Digestive Tract Cancer.
Glutathione reduces the toxicity and improves the quality of life of women diagnosed with ovarian cancer treated with cisplatin: results of a double-blind, randomized trial.
Neuroprotective effect of reduced glutathione on cisplatin-based chemotherapy in advanced gastric cancer: a randomized double-blind placebo-controlled trial.
Skin lightening ✪✪✪✪✪
Clinical research shows that daily intake of 500 mg of glutathione in combination with selenium, vitamin C, vitamin D3, vitamin E, and grape seed extract has a skin-lightening effect on women with brown or dark brown skin, compared to their initial skin color.
Posologie
Oral route
600 - 1200 mg
Synergies
An open-label, single-arm trial of the safety and efficacy of a novel preparation of glutathione as a skin-lightening agent in Filipino women.
The Clinical Effect of Glutathione on Skin Color and Other Related Skin Conditions: A Systematic Review
Oxidative stress ✪✪✪✪✪
Glutathione (GSH) is the principal endogenous intracellular antioxidant. It has many functions, including protecting cells from oxidative stress, detoxifying toxins and carcinogens, and maintaining immune function. Almost all body tissues synthesize GSH by the sequential addition of precursor amino acids, cysteine, glutamic acid, and glycine, through enzymatic catalysis using two ATP-dependent enzymes, glutamine cysteine ligase (GCL) and GSH synthetase (GS). Maintaining tissue levels of GSH is essential to preserve health, prevent diseases, and counteract age-related biological stress. Low GSH levels are associated with increased risks of many diseases, including cancer, cardiovascular diseases, arthritis, and diabetes. GSH levels depend on the availability of its precursor amino acids, Cysteine, glutamic acid, and Glycine, with Cysteine being most often considered a limiting factor. Oral GSH supplementation is one of the strategies to increase GSH levels in tissues. There is limited data on the bioavailability of GSH in humans. Although it has been found that GSH is absorbed and transported into human intestinal epithelial cells in vitro and in vivo into oral mucosal cells. A randomized double-blind clinical study on healthy subjects showed that GSH supplementation increases GSH reserves in the human body.
Posologie
Oral route
250 - 1000 mg
Athletic performance ✪✪✪✪✪
A small clinical study shows that taking 200 mg of glutathione in combination with 2 grams of L-citrulline per day for 4 weeks increased lean mass after 4 weeks of resistance training and was positively associated with muscle strength. However, after 8 weeks of resistance training, there was no significant difference in any of the measured variables.
Posologie
Oral route
200 mg
Synergies
Liver disorders ✪✪✪✪✪
Preliminary clinical research shows that taking 300 mg of glutathione per day for 4 months reduces alanine aminotransferase (ALT) levels by approximately 13% and triglyceride levels by approximately 16%, but has no impact on aspartate aminotransferase (AST) levels or liver stiffness, compared to baseline values in patients with NAFLD. The validity of these results is limited by the absence of a comparison group.
Posologie
Oral route
300 mg
Immune system strengthening ✪✪✪✪✪
Glutathione contributes to strengthening the body's defenses by stimulating the production of lymphocytes or interleukin from the immune system.
Posologie
Oral route
300 mg
Lymphocyte glutathione levels in children with cystic fibrosis
In vitro glutathione supplementation enhances interleukin-2 production and mitogenic response of peripheral blood mononuclear cells from young and old subjects
Glutathione deficiency is associated with impaired survival in HIV disease
Properties
Antioxidant
Glutathione is a tripeptide known as the most important non-enzymatic antioxidant in the human body. In fact, glutathione is present both in a reduced form known as reduced glutathione (GSH) before exerting antioxidant effects and in an oxidized form (GSSG) after having exerted antioxidant effects. GSH and GSSG form a ratio known as the GSH/GSSG ratio, whose modifications indicate changes in cellular oxidative balance. Glutathione is used as a substrate by antioxidant enzymes known as glutathione S-transferases (GST). Moreover, another group of enzymes called glutathione peroxidase (GPx) enzymes use glutathione tripeptides to reduce lipid peroxidation and hydrogen peroxide into water.
Usages associés
Neurological
Glutathione is synthesized by neurons and glial cells. In vitro, it has been suggested that glutathione protects against toxins by acting as an antioxidant. Additionally, there is evidence linking decreased glutathione to Parkinson's disease. However, it is unclear whether reduced levels of glutathione result from increased oxidative stress, which is associated with the pathogenesis of Parkinson's disease, or if glutathione depletion itself truly contributes to the pathogenesis of Parkinson's disease. Other evidence shows that glutathione deficit may potentiate the inflammation associated with Parkinson's disease by increasing the production and activity of inflammatory cytokines. Therefore, theoretically, glutathione supplementation may mitigate inflammation associated with Parkinson's disease.
Dermatological Effect
Glutathione supplements are commonly used with the purpose of lightening skin tone for aesthetic reasons. There are various proposed mechanisms explaining this effect, mainly revolving around the interactions of glutathione with tyrosinase, an enzyme involved in melanin synthesis. These proposed mechanisms include interference with the cellular transfer of tyrosinase to melanosomes (intracellular organelle where melanin is produced), causing increased synthesis of pheomelanin and reduced synthesis of eumelanin (these are two constituents of biological melanin, pheomelanin being lighter in color than eumelanin, yellow to red, its UV absorption capability is lower than that of eumelanin and thus protects less against UV damage). Another proposed mechanism is the elimination of peroxides from ultraviolet radiation, which induce tyrosinase activity.
Usages associés
Anticancer
Preliminary data suggest that glutathione intake from fruits and vegetables could be associated with a reduced risk of pharyngeal cancer.
Antiviral
Glutathione can inhibit the activity of enzymes that help the influenza virus colonize cells lining the mouth and throat. Flu-infected mice given glutathione-enriched drinking water show lower tissue virus levels than untreated mice. Human studies are needed to determine the effects of glutathione on influenza infection.
Safety dosage
Adult: 200 mg
Afssa considers that the available publications do not provide a sufficient basis to justify glutathione supplementation for healthy individuals receiving a varied, balanced diet with sufficient caloric intake to meet their needs. However, Afssa considers that there are no scientific objections to the additional intake (supplements and fortifications included) of glutathione at the dose of 50 mg/day proposed by the Dgccrf (directorate-general for competition, consumer affairs, and fraud prevention).
Precautions
Pregnant women: avoid
Avoid use due to lack of reliable and sufficient information.
Asthma: use with caution
Inhaled glutathione may cause bronchospasm in asthmatic subjects.
Breastfeeding women: avoid
Avoid use due to lack of reliable and sufficient information.
