Vitamin E DL-alpha-tocopherol (DL-alpha-tocopherol) is a synthetic form of vitamin E, a fat-soluble antioxidant that protects cell membranes from damage by free radicals, enhances the immune system, and helps prevent blood clots. It functions by donating a hydrogen atom to neutralize free radicals. While it is a form of Vitamin E, it's important to note that the natural form, RRR-alpha-tocopherol, is preferentially absorbed and has greater bioavailability than the synthetic DL-alpha-tocopherol, which contains eight different stereoisomers.