Vitamin E (alpha tocopherol) was first isolated from plant oils. The term tocopherol was used to name the initial four compounds that shared a similar structure: a complex ring and a long saturated side chain. Tocopherols are the primary fat-soluble antioxidants that help minimize the effects of free-radicals. Of the four compounds, designated as alpha, beta, delta and gamma tocopherols – alpha tocopherol has the greatest nutritional and biological value. Vitamin E (alpha tocopherol) may help: prevent polyunsaturated fatty acids from breaking down and combining with substances that may harm the body, maintain muscle and nerve function, bring nourishment to cells, strengthen capillary walls, protect red blood cells from being destroyed by poisons, such as hydrogen peroxide, in the blood, promote healthy immune function, and decrease platelet aggregation (thins blood). Solgar offers the natural "D" form of vitamin E (D-alpha tocopherol).