Glutathione

Powerful antioxidant tripeptide that brightens and protects skin.

Also known as: L-glutathione, reduced glutathione (GSH), gamma-glutamylcysteinyl-glycine

What it is

Glutathione is a naturally occurring tripeptide (three amino acids: glutamic acid, cysteine, and glycine) found in every cell. It's the body's master antioxidant, neutralizing free radicals and regenerating other antioxidants like vitamins C and E.

What it does

Glutathione reduces oxidative stress and inflammation, brightens skin by inhibiting tyrosinase (the enzyme that produces melanin), and supports skin barrier repair. It also helps detoxify heavy metals and environmental pollutants. When applied topically or taken orally, it can improve skin radiance and even out tone, though oral absorption is limited unless stabilized or delivered via liposomal formulation.

The evidence

Emerging to moderate evidence supports its antioxidant and skin-brightening effects in vitro and in small clinical studies; oral bioavailability is weak unless encapsulated. Strong evidence exists for its systemic antioxidant role, but topical efficacy in cosmetics remains less robust than for established brighteners like vitamin C or niacinamide.

Best for

Dull, uneven, or hyperpigmented skin; those seeking antioxidant protection and a brightening boost; clients interested in systemic wellness.

Pairs well with

Vitamin C, niacinamide, ferulic acid, and other antioxidants; liposomal or stabilized delivery systems enhance efficacy.

Use cautiously with

No major conflicts; however, combining with high-dose vitamin C may compete for antioxidant activity. Avoid excessive heat or oxidizing agents in formulation, as glutathione degrades easily.

Cautions

Topical glutathione is unstable and degrades quickly; look for stabilized or liposomal forms. Oral supplements are poorly absorbed unless encapsulated; IV or liposomal delivery is more effective. Pregnancy safety is not well established; consult a provider. May cause mild GI upset if taken orally.