Hyperpigmentation: Lightening the skin with Vitamin E?

Often extracted from vegetable oils, the vitamin E encompasses eight fat-soluble molecules, meaning they are soluble in fatty substances: 4 tocopherols and 4 tocotrienols. For stability reasons, alpha-tocopherol is the vitamin E most commonly used to formulate cosmetics and design dietary supplements. While it is primarily known for its moisturising properties, the benefits of this molecule extend further. Indeed, several studies have shown that vitamin E helps to prevent and reduce the appearance of pigmentation spots. It can thus be used to even out the complexion and restore its radiance.

Firstly, Vitamin E has an anti-radical activity. It protects the skin cells from the oxidative stress caused notably by the UV rays of the sun and exposure to tobacco or pollution. Vitamin E neutralises free radicals before they attack cellular constituents. More specifically, the free hydroxyl function carried by the aromatic cycle of this compound reacts with free radicals and provides them with the missing electron, which allows them to stabilise. Vitamin E then becomes a free radical in turn but remains relatively stable thanks to the double bonds of its cycle.

Furthermore, mechanistic studies have shown that alpha-tocopherol can inhibit tyrosinase, a key enzyme in melanogenesis. Indeed, tyrosinase catalyses the conversion of tyrosine into melanin. The inhibitory effect of alpha-tocopherol comes from its chemical structure, specifically its aromatic ring and its free hydroxyl function. This arrangement allows its hydroxyl group to bind to the active site of the enzyme, while its side chain can associate with the hydrophobic protein pocket near the active site. This blocks the activity of the tyrosinase enzyme, and therefore the synthesis of melanin.

The depigmenting properties of vitamin E, both when taken orally and applied topically, have been highlighted in several studies in vivo. However, it should be noted that the results are only visible after several months and that hyperpigmentation can only be reduced, not eliminated. For better efficacy of the vitamin E, scientists recommend combining it with vitamin C, a well-known depigmenting agent that also acts on tyrosinase. There is an interesting synergy between these two vitamins. Indeed, the redox potential of vitamin C, which is lower than that of vitamin E, allows the former to reduce the latter in order to regenerate its antioxidant and photoprotective activity.