There are eight natural, fat-soluble vitamin E forms, which are divided into four tocopherols and four tocotrienols. The four tocopherols are divided into alpha (α), beta (β), gamma (γ) and delta (δ) tocopherol with α-tocopherol being the most potent. All vitamins E are antioxidants. The body seems to prioritize alpha-tocopherol, which is the only form of vitamin E with a specific transport protein.
In dietary supplements, α-tocopherol can be added both as an active vitamin or in small amounts as an excipient to counteract oxidation of the preparations.
α-Tocopherol has E-number 307.