Vitamin E - Forms of

Vitamin E is not one single compound, rather a group of several related compounds.  This section describes the various forms of Vitamin E.

 All natural forms of Vitamin E occur in their "D" stereoisomer form.  Natural forms of Vitamin E are absorbed and retained better than synthetic forms of Vitamin E.  ^[1]

   Synthetic Vitamin E is a mixture of eight stereoisomers, and is designated DL-Alpha-Tocopherol. Only one of the eight stereoisomers (12.5%) in synthetic Vitamin E is identical to d-Alpha-Tocopherol.  The other seven have varying biological activity, ranging from 21% - 90% as active as d-Alpha-Tocopherol.  Synthetic Vitamin E is absorbed and retained far less efficiently than natural Vitamin E.  ^[2]

 d-Alpha-Tocopherol (also known as Natural Source Vitamin E) is the form of Vitamin E that is most commonly found in Vitamin E supplements.  This "natural" form of Vitamin E is more costly to isolate, concentrate, and manufacture than dl-Alpha-Tocopherol is to synthesize from petrochemicals and is therefore approximately twice as expensive as synthetic Vitamin E.  It has 1.4 times more Vitamin E IU activity compared to synthetic Vitamin E and is retained within the body far more efficiently than synthetic Vitamin E.  Each 1 mg of D-Alpha-Tocopherol possesses 1.49 IU of Vitamin E activity.  Alpha-Tocopherol is the major Tocopherol in human Blood Plasma - it accounts for 87% of the total Tocopherols concentration of human Blood Plasma.

 d-Alpha-Tocopherol Acid Acetate (also known as Natural-Source Vitamin E Acetate;  Tocopherol Acetate;  Tocopheryl Acetate) is the d-Alpha-Tocopherol form of Vitamin E combined with Acetic Acid to improve its water-solubility.  It is an esterified form of Vitamin E.  d-Alpha-Tocopherol Acid Acetate is not topically bioavailable (as Digestive Enzymes absent from the Skin are required for its activation).  Each 1 mg of d-Alpha-Tocopherol Acetate possesses 1.36 IU of Vitamin E activity.  After its absorption into the body, d-Alpha-Tocopherol Acetate, the Acetate molecule is stripped off to re-form d-Alpha-Tocopherol (by endogenous Esterase enzymes)  Some researchers regard d-Alpha-Tocopherol Actetate (together with d-Alpha-Tocopherol Succinate) as the preferable form of oral d-Alpha-Tocopherol supplementation as it is more stable than “free” d-Alpha-Tocopherol.