Intravenous administration generally provides higher bioavailability than intramuscular injections by delivering glutathione directly into the bloodstream, though glutathione exhibits a short plasma half-life in all forms, limiting prolonged effects. There is no conclusive evidence from high-quality comparative studies determining whether weekly IM injections or monthly IV infusions are superior overall; frequency recommendations often derive from clinical practices rather than robust trials. Both routes lack strong support for common off-label uses such as skin whitening, with reviews indicating insufficient evidence from well-designed studies, potential risks (particularly serious adverse effects with IV administration such as liver dysfunction and anaphylaxis), and better-supported alternatives like oral or topical forms in limited trials. Intramuscular glutathione injections are used in some clinical and cosmetic settings for purported benefits such as antioxidant support, skin lightening, detoxification, or management of conditions like Parkinson's disease or liver disorders, with typical dosages ranging from 600-1200 mg per injection administered 1-3 times weekly. Specific clinical studies have investigated 600 mg IM protocols for certain conditions, including male infertility (600 mg IM every other day for 2 months, or daily in some studies), non-alcoholic fatty liver disease (600 mg/day IM for 30 days, with improvements in liver enzymes and oxidative stress markers), and as an adjunct to chemotherapy (600 mg/day IM on days 2-5). No universal standard protocol exists for 600 mg intramuscular glutathione, as uses are often off-label and vary by condition. Evidence is limited to small studies, and some clinics use 600 mg IM as a single dose or weekly for antioxidant support. Consultation with a healthcare provider is recommended due to the limited evidence. No standardized, evidence-based dosage exists, and high-quality supporting evidence is limited or lacking, with most available studies being small, low-quality, or focused on intravenous rather than intramuscular administration. Glutathione injections are not approved by major regulatory bodies such as the FDA for these uses and are frequently employed off-label, often in wellness clinics. Safety concerns include risks of allergic reactions, injection-site infections, or other adverse effects; regulatory agencies have highlighted issues with compounded injectable glutathione products due to reported adverse events.In 2026, CDC and FDA investigated illnesses in patients who received compounded injectable glutathione made with a dietary supplement-grade ingredient. In August 2026, FDA reported at least 30 patients with adverse events after intravenous glutathione prepared by different compounding pharmacies that had all obtained the ingredient (lot 229536) from Medisca Inc.; reported symptoms, including

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These claims were echoed in a lawsuit filed by TFE Games Holdings on February 9, 2026, accusing Sharif and his husband of fraud and embezzlement, including misuse of company funds to cover a $6 million personal loan.By May 1, 2026, that lawsuit had been dismissed without prejudice, apparently by agreement of the parties.