How much is too much? When an antioxidant becomes a pro-oxidant

Tocopherols (vit E) are available at different concentrations in fruits, seeds and nuts and in the related oils and lipophilic extracts. They are available as dietary supplement as antioxidants, rejuvenating, wound healing, improving eye-sight properties to name a few.

Tocopherols are added to plant oils (specially refined plant oils) as an antioxidant to slow down the inevitable oxidation process of the oil. They are added in food and beverages both for the sake of slowing down the process of oxidation and rancidity.

In personal care we add tocopherols in finished products for the very same reasons:

1- protection of the skin and hair lipids agains oxidation

2- Protection of the lipids (unsaturated fatty acids) in the formulation

All that is common knowledge and nothing worth winning a Nobel prize or any prize for that matter.

There is a fact however that is less known to formulators and specially to novice formulators and that is the pro-oxidant activity of tocopherols at higher concentrations.

During the last years I have observed many enthusiastic novice formulators and INDIE brands adding high concentrations of tocopherols to their formulations just to jazz-up their formulations and add value.

Here again we have one of those cases where less-is-better otherwise we will fall from the other side of the roof and accelerate the oxidation in the formulation instead of prolonging the shelf-life.

References and further reading:

Tavadyan, Levon, et al. "WHY IS THE ANTIOXIDANT POTENCY OF Α-, Β-, Γ-AND Δ-TOCOPHEROLS DEPENDING ON CONCENTRATION REVERSAL?." Functional Foods and Bioactive Compounds: Modern and Medieval Approaches (2023): 317.

Pegg, Ronald B., and Ryszard Amarowicz. "11 Prooxidants and." Chemical and Functional Properties of Food Components (2023): 303.

Cillard, J., P. Cillard, and M. Cormier. "Effect of experimental factors on the prooxidant behavior of α-tocopherol." Journal of the American Oil Chemists’ Society 57.8 (1980): 255-261.