Dl-alpha-tocopheryl acetate is an all-synthetic form of alpha-tocopherol. An alternative natural form of stable vitamin E is d-alpha-tocopheryl acetate, which is derived from vegetable oils and exists in the form of one isomer. D-alpha-tocopheryl acetate is the acetate ester of natural-source d-alpha-tocopherol. D-alpha-tocopheryl acetate is produced by coupling racemic isophytol with trimethylhydroquinone to form d1-tocopherol. Vitamin E forms are listed as either plain "tocopherol" or tocopheryl followed by the name of what is attached to it, as in "tocopheryl acetate". The two forms are not greatly different. However, plain tocopherol may be absorbed a little better, while tocopheryl attached forms have a slightly better shelf life.