When to Stop

• Anaphylactoid reaction — bronchospasm, urticaria, hypotension. More common with rapid push and with non-sterile or contaminated preparations.
• Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) — documented in case reports from cosmetic skin-lightening contexts in Asia. Very rare in physician-supervised therapeutic settings with sterile compounding.
• Sepsis / injection-site infection from non-sterile preparations or poor injection technique.
• Contamination-related serious adverse events — endotoxin reactions, particulate matter, content variability in unregulated black-market vials.
• Hypothyroidism — rare reports from chronic high-dose cosmetic protocols (mechanism unclear; possibly tyrosinase-related cross-reactivity with thyroid peroxidase).
• Endogenous GSH is essential for fetal redox homeostasis. Hard-block for pregnant or breastfeeding users in the encyclopedia framework due to (a) limited safety data for IV/IM at therapeutic doses during pregnancy and (b) sterility / contamination risk amplification.
• Endogenous molecule with millimolar tissue concentrations — supplementation at sub-saturating doses has minimal toxicity concern in a sterile, physician-supervised setting.
• The biggest practical risks are contamination, injection-site infection, and severe cutaneous reactions in unregulated cosmetic clinics. These are not theoretical; the FDA / Philippines FDA warnings are based on real adverse-event reports.
• Theoretical immune-suppressive at chronic high doses — GSH biases immunity toward Th1/cellular; chronic mega-dosing could in theory reduce Th2 / antibody responses. Not practically observed at standard therapeutic doses.
• No formal NOAEL established for IV GSH. Single push doses to 5000 mg have been used without major concern in research settings. Chronic 1200 mg IV TIW x 4 months (Honda 2017) without serious adverse events in NAFLD population.