Vitamin E (d-Alpha Tocopherol) is all natural Vitamin E 1000IU that can be used as an antioxidant to extend shelf life of oil based products. Although there are other 'mixed tocopherol' types of Vitamin E this is 100% all natural and does not contain a mixture of tocopherols. The recommended usage rate, because each gram contains 1000IU, is one gram per 8 ounces (224 gm) of oil.
To be clear, Vitamin E is not a preservative but is an antioxidant with skin care benefits. Oils with very short shelf life, 6 months to a year, can benefit with the addition of Vitamin E because of its antioxidant properties that works to inhibit oxidation in fragile oils.