Vitamin E, in its natural form, comprises eight different compounds: alpha-, beta-, gamma-, and delta-tocopherols and alpha-, beta-, gamma-, and delta-tocotrienols. Tocopherols and tocotrienols are important for human health. Known as the "master antioxidant," vitamin E has the ability to mitigate oxidative stress, and antioxidant-related effects on various organs and systems have been extensively researched. More recently, non-antioxidant mechanisms have been proposed, such as those affecting cellular signal transduction and gene expression.