Aim for organic and pasture-raised, as these will have the most abundant nutrients
This product contains the reduced form

Numbuzin No.5+ Glutathione Vitamin Concentrated Serum ingredients (INCI) Vaccinium Vitis-Idaea Fruit Extract, Butylene Glycol, Niacinamide, Panthenol, Tranexamic Acid, Water, 1,2-Hexanediol, Neopentyl Glycol Dicaprate, Caprylic/Capric Triglyceride, Sorbitol, Bifida Ferment Lysate, Chondrus Crispus Extract, Butyrospermum Parkii (Shea) Butter, Saccharum Officinarum (Sugar Cane) Extract, Alpha-Arbutin, Sodium Hyaluronate, Melia Azadirachta Flower Extract, Ocimum Sanctum Leaf Extract, Melia Azadirachta Leaf Extract, Curcuma Longa (Turmeric) Root Extract, Corallina Officinalis Extract, Tremella Fuciformis (Mushroom) Extract, Pentylene Glycol, Glycerin, 3-O-Ethyl Ascorbic Acid, Bisabolol, Tromethamine, Ethylhexylglycerin, Adenosine, Hydrogenated Lecithin, Allantoin, Glutathione, Ceramide NP, Beta-Glucan, Dipotassium Glycyrrhizate, Tocopherol, Ascorbic Acid, Ascorbyl Glucoside, Tocopheryl Acetate, Hydroxypropyl Cyclodextrin, Ubiquinone, Lipoic Acid, Potassium Hydroxide, Behenyl Alcohol, Carbomer, Xanthan Gum, Disodium EDTA

doi: 10.1016/j.freeradbiomed.2018.01.023 11 LimJKMDelaidelliAMinakerSWZhangHFColovicMYangHet al
Just remember SPF