From the Guidelines
Glutathione supplements are generally considered safe, but high doses may induce nausea, anorexia, and mild ataxia, and rare cases of anaphylaxis have been reported with high IV doses. The side effects of glutathione supplements can vary based on the dosage and administration method. Common side effects include abdominal cramps, bloating, gas, and occasional allergic reactions like rash or itching [ 1 ]. Some people report experiencing nausea, diarrhea, or headaches after taking glutathione. When administered intravenously, there's a risk of zinc deficiency with long-term use. Inhaled forms may trigger asthma symptoms in sensitive individuals.
Key Considerations
- The typical oral dosage ranges from 250-1000mg daily, while intravenous doses are determined by healthcare providers based on individual needs.
- People with asthma should be cautious with inhaled forms, and those taking certain medications (particularly chemotherapy drugs) should consult their doctor before supplementing, as glutathione might interfere with medication effectiveness.
- These side effects occur because glutathione is a powerful antioxidant that affects various biochemical processes in the body, and individual responses can vary based on dosage, administration method, and personal health factors.
- If side effects persist or worsen, discontinuing use and consulting a healthcare provider is recommended.
Administration and Monitoring
- High IV doses of glutathione have rarely led to anaphylaxis [ 1 ].
- Doses of more than 400 mg may induce nausea, anorexia, and mild ataxia [ 1 ].
- The only effect of doses in excess of needs is increased urinary excretion [ 1 ].
From the Research
Glutathione Side Effects
- The safety of S-Acetyl Glutathione (SAG) supplementation was assessed in various studies, including an in vitro bacterial reverse mutation assay, an in vitro micronucleus test, an acute oral toxicity study, and a repeated dose (13 week) toxicity study 2.
- The results of these toxicological studies support the safe use of SAG in foods or dietary supplements, with no mortality or morbidity resulting from the acute oral toxicity study (LD50 > 2000 mg/kg) and no treatment-related gross or histopathology findings observed in any organs 2.
- Administration of SAG over 13 weeks was well tolerated and did not result in any neurobehavioral alterations or effects on locomotor activity, ophthalmology, hematology, coagulation, blood biochemistry, urinalysis, thyroid hormones or the male reproductive system 2.
- Mild increases noted in liver, kidney and spleen weights were non-adverse and within historical control ranges, and the NOAEL was determined to be 1500 mg/kg/day, the highest dose tested 2.
Interaction with Other Compounds
- Vitamin E has been shown to interact with glutathione-dependent enzymes, with protective effects on these enzymes and prevention of damaging effects of reactive oxygen species on polyunsaturated fatty acids in biomembranes (lipid peroxidation) 3.
- The interaction between vitamin E and glutathione-dependent enzymes is complex, with antioxidants such as vitamin E forming an intricate network with glutathione-dependent enzymes to protect against oxidative stress 3.
Food Allergies and Glutathione
- While there is no direct evidence of glutathione side effects related to food allergies, common food allergens such as cow's milk, egg, peanut, tree nut, soy, wheat, fish, and shellfish can induce an allergic reaction, and recognition of symptoms and management of reactions are important for patients and practitioners 4.
- Diagnosis of food allergy includes skin prick testing, specific serum IgE testing, and oral food challenges, and management is centered on avoidance of allergenic and cross-reacting foods and early recognition and immediate treatment of reactions 4.