What it is
L-glutathione is a tripeptide of glutamate, cysteine and glycine, and the most abundant intracellular thiol antioxidant in human cells. It appears in redox biology, hepatology and dermatology research, where it is studied in reduced and oxidized forms.
How it works
Glutathione neutralises reactive oxygen species and supports phase II conjugation reactions. In pigmentation research it is thought to inhibit tyrosinase and shift melanin synthesis from eumelanin toward pheomelanin.
Regulatory status
- Cosmetic ingredient
- Research compound
- In clinical trials
- Approved medicine
Not approved as a medicine by the FDA or the EMA. Some are registered in individual countries. Supplied for laboratory research only.
What published research is studying
- Skin melanin index in healthy adults (randomized placebo-controlled trials)
- Melasma and other hyperpigmentation disorders (systematic reviews of oral, topical and intravenous forms)
- Wrinkle depth, skin elasticity and UV spot counts
- Oral bioavailability, which is limited by breakdown in the gut
Key findings
In a 4-week randomized double-blind trial in 60 healthy adults, oral glutathione lowered the melanin index more than placebo at 2 of 6 measured sites.
Arjinpathana N and Asawanonda P, J Dermatolog Treat 2012In a 12-week three-arm randomized trial in healthy women, reduced and oxidized glutathione both tended to lower melanin index, and wrinkle reduction reached significance at some sites.
Weschawalit S et al., Clin Cosmet Investig Dermatol 2017A systematic review of 4 clinical studies concluded that the skin-lightening evidence for glutathione remains inconclusive, because of study quality and inconsistent findings.
Dilokthornsakul W et al., J Cosmet Dermatol 2019A 2025 systematic review counted 5 randomized trials of oral glutathione reporting melanin index reductions versus placebo, while the one intravenous placebo-controlled study showed no significant difference.
Sarkar R et al., Int J Dermatol 2025
What the studies measured
Study durations
- Oral glutathione whitening trial: 4 weeks in 60 participants (Arjinpathana 2012).
- Reduced and oxidized glutathione trial: 12 weeks, with measurements at each visit (Weschawalit 2017).
Endpoints
- Skin melanin index by reflectance measurement
- UV spot count on standardized facial imaging
- Wrinkle depth and skin elasticity
- Colorimetric L* value
- Safety laboratory panels and adverse events
How strong is the evidence?
Several small randomized human trials exist, mostly in dermatology and running 4 to 12 weeks, but systematic reviews still describe the pigmentation evidence as inconclusive.
Common questions
Is Glutathione an approved medicine?
Research compound. Not approved as a medicine by the FDA or the EMA. Some are registered in individual countries. Supplied for laboratory research only.
How much human research is there on Glutathione?
Several small randomized human trials exist, mostly in dermatology and running 4 to 12 weeks, but systematic reviews still describe the pigmentation evidence as inconclusive.
Does UU supply Glutathione?
Yes, as premium-grade research material for laboratory use. Every batch is tested by an independent lab and the certificate of analysis is published.