Antioxidant
L-Glutathione Reduced
Also known as: Reduced Glutathione, GSH, L-γ-Glutamyl-L-cysteinyl-glycine, Glutathione (reduced form)
L-Glutathione is a tripeptide antioxidant naturally produced in cells that helps neutralize free radicals and support detoxification processes. Oral bioavailability is limited due to rapid degradation in the digestive tract, though some studies suggest reduced forms may be better absorbed than oxidized forms.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Primary uses
- Antioxidant support
- Cellular detoxification
- Immune function support
- Liver health
- Detoxification support
- Cellular health
- Oxidative stress reduction
How it works
- Direct antioxidant activity via conjugation with free radicals and oxidative species
- Cofactor for glutathione peroxidase and glutathione S-transferase enzymes
- Regeneration of other antioxidants (vitamins C and E)
- Protein synthesis and DNA repair support
Dosage
- Typical range
- 250–1000 mg daily
- Timing
- Any time of day; with or without food
- With food
- No strong preference; some sources suggest taking with vitamin C to enhance absorption
- Duration
- Safety data supports continuous use; optimal duration for therapeutic benefit unclear
- Special populations
- Pregnant/nursing women should consult practitioners; limited safety data in pediatric populations
Forms
- Powder· 70/100
- Capsule· 70/100
- Tablet· 70/100
- Liposomal· 70/100
- S-Acetyl Glutathione· 70/100
- Sublingual· 70/100
Safety
Common side effects
- Generally well tolerated at typical doses
- Rare: mild gastrointestinal upset
- Rare: headache or skin reactions
Contraindications
- Avoid in individuals taking cisplatin or other chemotherapies (may reduce efficacy)
- Caution in patients with cystinuria or homocystinuria
- Limited data in pregnancy—consult healthcare provider
Products containing L-Glutathione Reduced
Top-scoring supplements in our catalog that list L-Glutathione Reduced on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
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Evidence notes
Oral glutathione has limited bioavailability; most human studies show modest systemic absorption. Some evidence supports IV forms in clinical settings, but oral supplementation evidence is preliminary. Well-established physiological importance does not translate to strong oral supplement efficacy data.
Grade C: Mostly observational or small trials; mechanism is plausible but unproven at scale.
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.