Side by side

1. 1.Neutralises reactive oxygen species through its cysteine thiol group.
2. 2.Acts as the required cofactor for glutathione peroxidase and glutathione transferases, which disarm peroxides and drug metabolites.
3. 3.Recycles vitamins C and E back into their active forms.
4. 4.Oral glutathione is largely broken down in the gut, which is why infused forms are claimed to work better — a claim with limited human support.
5. 5.Skin lightening is proposed to work by shifting melanin production toward lighter pigment; the supporting trials are small and short.

• Skin pigmentation and 'brightening'
• Antioxidant and liver-support claims
• Chemotherapy-induced nerve damage (adjunct)
• Male infertility and sperm oxidative stress
• Parkinson's disease (intravenous, phase 2)

• Measured glutathione levels rise transiently
• Modest, inconsistent skin-lightening effects in small studies
• Lower oxidative-stress markers
• No demonstrated clinical benefit for most marketing claims

• Abdominal cramps, bloating and loose stools with oral use
• Flushing, chills or chest tightness during infusion
• Rare bronchospasm with inhaled glutathione
• Infection and vein injury from unsupervised intravenous use

Research context only — there is no approved protocol for elective use. Studies have used oral doses of roughly 250–1000 mg daily, inhaled forms, and intravenous doses in the 600–2400 mg range given by a clinician. Intravenous use carries the risks of any infusion and belongs in clinical hands. 'Two to three times a week for 6–12 weeks' schedules circulate online but are not validated regimens.

Research context only