Glutathione injection is promoted for skin lightening by inhibiting tyrosinase and shifting melanin toward pheomelanin, but evidence for intravenous use is limited, effects are often temporary, and safety concerns include hepatotoxicity, hypersensitivity, and rare severe reactions; several regulators have issued cautions against cosmetic IV use outside controlled settings. Oral and topical forms show modest melanin reduction with better tolerability, though results vary and durability is uncertain, warranting cautious, supervised use and rigorous photoprotection. Any parenteral regimen should be specialist‑directed with quality‑assured products, baseline labs, and clear goals given the unsettled benefit‑risk balance.