Vitamin E

Tocopherol is the INCI name for vitamin E, a fat-soluble antioxidant found naturally in skin, where it concentrates in sebum and in cell membranes.

How it works

Tocopherol works in the lipid phase. It donates a hydrogen atom to lipid peroxyl radicals, halting the chain reaction of lipid peroxidation before it can propagate through a membrane. This makes it a chain-breaking antioxidant rather than one that neutralises radicals on contact and stops there.

Once it has donated that hydrogen, tocopherol is itself oxidised and inactive. It can be regenerated back to its active form by vitamin C and by ubiquinone, which is the reason these three are so often formulated together.

In the skin barrier

Tocopherol is a normal constituent of sebum and of the lipid layers of the stratum corneum, where it protects those lipids from oxidation. It is depleted by UV exposure and by environmental pollutants.

In formulation

Beyond its role on skin, tocopherol also protects the oils within a formula from going rancid, so it frequently appears at low levels as a stabiliser rather than as an active. Its position in the ingredient list is a rough guide to which job it is doing.

Tocopheryl acetate is a more stable ester form, converted to tocopherol by skin enzymes after application.