Ingredient profile
Vitamin E is one of the easiest functional ingredients to misunderstand. It can help slow oxidation in oil-heavy formulas, especially when delicate oils are present, but it does not preserve water-containing products.
Use it in beard oils, balms, and butters when oxidation is the concern. If water, aloe, glycerin-heavy formulas, or washes enter the formula, you still need to choose a real preservative.
For the Science Hippies
Tocopherol is oil soluble and used to support oxidative stability in lipid systems. It should be framed as an oil antioxidant, not as a preservative for products that contain water.
In beard oils and balms, it is most useful when the formula includes delicate oils or when the maker wants an a little extra help slowing oil rancidity. It can add color or odor depending on grade and level.