Vitamin E consists of a family of 8 naturally occurring, fat-soluble isomers - 4 Tocopherols (alpha, beta, gamma and delta) and 4 Tocotrienols (alpha, beta, gamma and delta).
Tocotrienols’ and tocopherols’ molecular structures differ in that tocotrienols have three unsaturated double bonds on the side chain while tocopherols have a saturated side chain. 
Tocotrienols’ polyunsaturated molecular structure facilitates a more efficient distribution of tocotrienol molecules at the cellular level, allowing it to be much more effective as an antioxidant.
Each isomer of tocotrienols also has its own unique structure, conferring
the special benefits it can provide for the human body. Therefore, it is crucial for an effective Vitamin E supplementation program to include the full spectrum of all four tocotrienol isomers and alpha-tocopherol. For more information on these benefits, please click on Benefits of Tocotrienols.