Vitamin E is a crucial lipid-soluble antioxidant in the human body, acting as a free radical protector for structures possessing high lipid levels including cell and organelle membranes, lipoprotein particles, and the central nervous system. Numerous clinical studies have documented Vitamin E's positive effect on immunity, circulation and joint health.* E-400 is derived from natural sources and includes all 4 vitamers (alpha, beta, gamma & delta), thereby resembling the variety of forms naturally found in food. Plus, the product is unesterified.