Interesting research
Vitamin E
INCI: Tocopherol · also alpha-tocopherol, tocopherol, vitamin E
The main fat-soluble antioxidant in cell membranes and in the skin's surface lipids. In a vitamin C serum it does two jobs at once: it protects the lipid phase, and it keeps the vitamin C company.
Why it is here
Vitamin C's oil-soluble partner. The two regenerate each other, which is more than most relationships manage, and the pair protects more than either does alone.
Vitamin C is water soluble and vitamin E is oil soluble, so between them they cover both compartments where ultraviolet light generates free radicals. They also regenerate each other: ascorbate reduces the tocopheroxyl radical back to tocopherol, so the pair lasts longer than either alone. That recycling loop is why the combination outperforms the sum of its parts in the photoprotection work.
The receipts
1 percent alpha-tocopherol alone was protective against erythema and sunburn cell formation, but the combination with 15 percent L-ascorbic acid was superior and reached an antioxidant protection factor of 4-fold.
UV photoprotection by combination topical antioxidants vitamin C and vitamin E. Journal of the American Academy of Dermatology, 2003. in vivo animal, n = pig skin, 4 days of application. PMID 12789176
Topical alpha-tocopherol protects through combined antioxidant and ultraviolet-absorbing properties and inhibits cyclobutane pyrimidine photoproduct formation in mouse skin, but is itself rapidly depleted by UVB in a dose-dependent way.
Photoprotective actions of topically applied vitamin E. Drug Metabolism Reviews, 2000. review. PMID 11139138
In practice
- Typical use
- 0.5 to 2 percent in serums and creams. 1 percent alpha-tocopherol is the level used in every paper in the vitamin C and E photoprotection series.
- Pairs with
- L-Ascorbic Acid, Ferulic Acid, Vitamin C + E + Ferulic, Squalane
- Keep apart from
- Nothing meaningful. Vitamin E is a stabilizer as often as it is an active, and it plays well with the oil phase of almost anything.
- Cautions
- Tocopherol is a recognized, if uncommon, contact allergen, mostly reported from high-dose leave-on products. It is oil soluble, so in very rich formulas some people find it heavy. Sun protection still comes from sunscreen.
Questions people ask
Why is vitamin E in the interesting tier and not the good one?
Because the human trial data is for the combination, not the molecule alone. The standalone photoprotection work is in mouse and pig skin. Vitamin E earns its place in Bright Side through the recycling relationship with vitamin C, which is well established, but we are not going to file that under human clinical evidence when it is not.
Is the vitamin E in skincare the same as the capsule I swallow?
Same family, different job. Oral vitamin E raises circulating tocopherol. Topical tocopherol loads the stratum corneum and sebaceous lipids directly, which is where photo-oxidation starts. The topical route is what the photoprotection studies used, and the two are not interchangeable for this purpose.
Does vitamin E break down in the bottle like vitamin C does?
It degrades more slowly, which is part of why it is used as a stabilizer for other oils. Under ultraviolet light it is depleted rapidly and dose dependently, so it works best on skin that also has sunscreen over it. In the bottle its main enemies are the same as everything else: air, light and heat.