Reduced vs oxidised glutathione (GSH vs GSSG): which is better for skin?
What reduced and oxidised glutathione are, why creams use one or the other, and what to check on the label.
- Reduced glutathione (GSH) is the active form; oxidised (GSSG) is two joined molecules the body recycles.
- GSSG is more stable in creams and was used in the best-known lotion study.
- Packaging, the full formula and sunscreen matter more than the form.
What is the difference between reduced and oxidised glutathione?
Reduced glutathione (GSH) is the active antioxidant form. After it neutralises a free radical, two molecules join into oxidised glutathione (GSSG). The body turns GSSG back into GSH with an enzyme, so the two forms cycle.
Is oxidised glutathione better for skin creams?
Oxidised glutathione is more stable in water-based formulas, and the best-known cream study used it. There is no head-to-head study showing one form works better in a cream.
The two forms in one table
| Reduced (GSH) | Oxidised (GSSG) | |
|---|---|---|
| What it is | One glutathione molecule, active | Two glutathione molecules joined |
| In the body | Most of the glutathione in healthy cells | Formed after antioxidant work, then recycled |
| Stability in products | Oxidises with air and water | More stable |
| Skin studies | 250 mg tablets, 12 weeks (Weschawalit et al., 2017) | 2% lotion, 10 weeks (Watanabe et al., 2014); 250 mg tablets (Weschawalit et al., 2017) |
What the studies used
The 10-week lotion study used oxidised glutathione and found a lower melanin index than placebo (Watanabe et al., 2014). A 12-week tablet study compared both forms; both trended towards lower melanin, and the reduced form also showed some wrinkle improvement (Weschawalit et al., 2017). A 2025 review found no strong reason to prefer one form in creams (Khanna et al., J Clin Aesthet Dermatol 2025).
What matters more than the form
- Packaging: an airtight, opaque jar or tube protects glutathione from air and light. Close the lid after use.
- The whole formula: partners like niacinamide and vitamin C do much of the work.
- Regular use and sunscreen: they decide results more than GSH vs GSSG.
- A faint sulphur smell is normal for glutathione products.
On labels
You may see "glutathione", "reduced glutathione", "L-glutathione" or "oxidised/oxidized glutathione". All are the same molecule family; check the full ingredient list and honest claims.
- Watanabe F, et al. Skin-whitening and skin-condition-improving effects of topical oxidized glutathione: a double-blind and placebo-controlled clinical trial in healthy women. Clin Cosmet Investig Dermatol. 2014.
- Weschawalit S, Thongthip S, Phutrakool P, Asawanonda P. Glutathione and its antiaging and antimelanogenic effects. Clin Cosmet Investig Dermatol. 2017;10.
- Khanna R, Rambhia P, Chapas A. Systematic review of the efficacy and safety of topical glutathione in dermatology. J Clin Aesthet Dermatol. 2025;18(9):51-54.
General information about cosmetic skincare, not medical advice. Results vary from person to person. See a dermatologist for persistent or changing pigmentation.
More glutathione guides
Glutathione: what it is, what it does for skin, and how to use it safely
The complete guide: what glutathione is, how it affects skin, every form compared, and the research.
GuideLiposomal glutathione: what it is, does it work for skin, and is it safe?
What "liposomal" means, what the studies on liposomal and regular glutathione supplements found, and what is still unknown for skin.
GuideGlutathione: key facts and figures, with sources
The essential numbers on glutathione for skin in one place: studies, doses, timelines and safety, each with its source.
