Tocotrienols are fat-soluble substances closely related to vitamin E. Like vitamin E, they have antioxidant properties, and help protect fatty substances in the body from being damaged by free radicals. In the 1990s, antioxidant supplements were thought to offer great potential for preventing a variety of diseases, including cancer and heart disease, and on this basis tocotrienols were offered on the market as healthful supplements. Tocotrienols have also been proposed for reducing cholesterol. However, subsequent studies have tended to pour cold water on all these hopes. At present, there is no reliable evidence that tocotrienols offer any meaningful health benefits.

Tocotrienols are not essential nutrients. They occur naturally in the oil extract of barley, palm fruit, rice bran, and wheat germ. Most commercially available supplements are made from rice bran oil or palm oil.