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Glutathione

Supplement antioxidant / tripeptide skin & hairimmune
Aka: L-glutathione, reduced glutathione, liposomal glutathione
Brands seen in Singapore: California Gold Nutrition, Life Extension, NOW Foods, Codeage, Aurora Nutrascience
Third-party tested: Codeage certifies other products with NSF Certified for Sport, but nothing for glutathione.Certification is granted per product, so check the tub you actually own. Not being listed is not the same as failing.
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Limited evidence — skin lightening; redox and immune markers
When to take
Daily
Studied for
The 30-day safety arm dosed 600 mg a day
Pros & cons
Pros
  • Oral doses lowered melanin, but results varied
  • 30 days at 600 mg: no change in alt, ast or creatinine
  • Gi discomfort was the most reported side effect
Cons
  • Iv use: anaphylaxis and liver harm reported
  • No standardised dosing; trials are small and short
  • The bioavailability trial was one brand, n = 14
Sources
  1. Exploring the Safety and Efficacy of Glutathione Supplementation for Skin Lightening: A Narrative Review (Cureus 2025) · read 2026-08-27
    what it says
    “Oral administration shows significant but variable decreases in melanin levels with limited side effects … Intravenous glutathione … is associated with serious safety concerns like anaphylaxis and hepatotoxicity, further aggravated by a lack of standardized dosing protocols”
  2. Cureus 2025 narrative review — evidence gap · read 2026-08-27
    what it says
    “Current evidence supports glutathione's potential as a depigmenting agent but underscores the need for rigorous, large-scale clinical trials to establish long-term safety, optimal dosing, and standardized applications”
  3. A Targeted Metabolomic Assessment of Oral Glutathione Bioavailability and Safety in Humans: A Randomized Crossover Clinical Trial (Antioxidants 2026) — design · read 2026-08-27
    what it says
    “a randomized, double-blind, crossover study was conducted in healthy adults (n = 14) to assess whole-blood GSH following single oral doses”
  4. Antioxidants 2026 crossover trial — pharmacokinetics · read 2026-08-27
    what it says
    “Compared with STD (500 mg), LMG (300 mg) produced significantly higher baseline-adjusted systemic GSH exposure and peak response (iAUC0-24: 1287.5 ± 179.0 vs. 517.8 ± 180.0 µg·mL·h; p = 0.0064)”
  5. Antioxidants 2026 crossover trial — 30-day safety arm · read 2026-08-27
    what it says
    “No significant changes in clinical safety markers (e.g., ALT, AST, ALP, creatinine) were observed following 30 days of daily LMG administration at 600 mg/d”
  6. Efficacy and Safety of Glutathione Supplementation in Patients with HIV Infection and HIV-Tuberculosis Co-Infection (Nutrients 2026) — mechanism · read 2026-08-27
    what it says
    “glutathione repletion … can restore intracellular thiol balance, improve immune cell function, enhance mitochondrial performance, and reduce systemic oxidative stress”
  7. Nutrients 2026 review — tolerability · read 2026-08-27
    what it says
    “These interventions have shown consistent safety and tolerability across diverse populations … with gastrointestinal discomfort being the most commonly reported adverse effect and serious toxicities remaining rare”
  8. Nutrients 2026 review — limitations · read 2026-08-27
    what it says
    “translation into routine clinical practice remains limited by methodological heterogeneity, short study durations, and lack of standardized biomarkers and long-term outcome data”
  9. HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev. No. 001 (Oct 2025) · read 2026-08-27
    what it says
    “The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list”
  10. iHerb Singapore — Glutathione & Antioxidants category (default order); first 5 distinct brands in page order: California Gold Nutrition, Life Extension, NOW Foods, Codeage, Aurora Nutrascience · read 2026-08-27
    what it says
    “L-Glutathione (Reduced), 500 mg, 120 Veggie Capsules … Glutathione, Cysteine & C, 100 Capsules … Glutathione, 500 mg, 120 Veg Capsules … Liposomal Glutathione, 60 Vegetable Capsules … Mega-Pack+®, Liposomal Glutathione, 32 Packets”
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Updated 2026-08-30. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.