Alpha-tocopherol is the primary form of vitamin E that is preferentially used by the human body to meet appropriate dietary requirements. In particular, the RRR-alpha-tocopherol (or sometimes called the d-alpha-tocopherol stereoisomer) stereoisomer is considered the natural formation of alpha-tocopherol and generally exhibits the greatest bioavailability out of all of the alpha-tocopherol stereoisomers. Moreover, manufacturers typically convert the phenol component of the vitamin to esters using acetic or succinic acid, making a compound such as alpha-tocopherol succinate more stable and easier to use in vitamin supplements 6,7.
Alpha-tocopherol succinate is subsequently most commonly indicated for dietary supplementation in individuals who may demonstrate a genuine deficiency in vitamin E. Vitamin E itself is naturally found in various foods, added to others, or used in commercially available products as a dietary supplement.
Reference
https://go.drugbank.com/drugs/DB14001
https://www.healthline.com/health/food-nutrition/truth-about-vitamin-e-oil