Glutathione (injectable)
A tripeptide antioxidant (glutamate-cysteine-glycine) central to cellular redox balance and detoxification. Injectable/IV glutathione is heavily marketed for skin lightening and general 'wellness', but robust clinical evidence for these cosmetic uses is weak; its established roles are biochemical and in specific medical settings.
01 Overview
Glutathione is the body's principal intracellular antioxidant, buffering oxidative stress and supporting phase-II detoxification and cysteine transport. It is synthesised endogenously, and oral bioavailability is poor, which drives the marketing of injectable and IV forms.
The popular use — intravenous or subcutaneous glutathione for skin whitening — rests on the idea that it shifts melanin synthesis toward lighter pheomelanin, but supporting trials are small, short and low-quality, and safety of repeated high-dose parenteral use is not well established. It is a genuine and important molecule biochemically, but the cosmetic injectable claims are far ahead of the evidence.
02 Mechanism
Acts as a reducing agent and cofactor for glutathione peroxidase/transferase enzymes; skin-lightening claims are attributed to inhibition of tyrosinase and a shift toward pheomelanin, though this is poorly substantiated in vivo.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Wellness injection (unproven) | 100–200 mg | SubQ | Grey-market wellness dosing without validated benefit. |
| Cosmetic skin-lightening (unproven) | 600–1200 mg | IV | Commonly marketed IV doses; not an evidence-based or approved use. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Antioxidant / redox supportCentral to cellular antioxidant defence; systemic supplementation benefit is less clear. | Biochemically established | Preclinical | |
| Skin lighteningMarketed to lighten skin; supporting evidence is limited and low-quality. | Small, short-lived in weak trials | Disputed |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Infusion/injection reactionsRash, injection-site reaction or, rarely, hypersensitivity with parenteral use. | Moderate | Uncommon | Observational | |
| Unregulated cosmetic-use risksHigh-dose skin-whitening use has prompted regulator warnings over unknown long-term safety and possible serious reactions. | Moderate | Unknown | Anecdotal |