Oxothiazolidinecarboxylic acid (procysteine) ek cysteine derivative hai jo skincare mein use hota hai. Yeh ek precursor ki tarah kaam karta hai jo body ke andar glutathione banane mein madad kar sakta hai. Glutathione ek powerful antioxidant hai, isliye yeh ingredient skin ko free radicals se bachane aur skin ko condition karne ke liye useful mana jaata hai.