glutathione face toner L-Glutathione Vitamin Boosting Toner, 5.07 fl oz (150 ml) MEDI-PEEL Bio-Intense Glutathione White Silky

Anal Chem 83:661665 Mourad T, Min KL, Steghens JP (2000) Measurement of oxidized glutathione by enzymatic recycling coupled to bioluminescent detection

Higher concentrations aren't necessarily better and may increase irritation risk without proportional benefits

Additionally, blood NAD + levels were significantly increased

Tatarkiewicz K, Sablan EJ, Polizzi CJ, Villescaz C, Parkes DG

As a direct antioxidant, GSH quenches reactive oxygen species (ROS), reactive nitrogen species (RNS), and lipid peroxyl radicals, and regenerates oxidised vitamin E and vitamin C back to their active reduced forms placing GSH at the hub of the broader cellular antioxidant network