In short
Vitamin C is an antioxidant: it can neutralize oxidants such as those from pollution and ultraviolet radiation.
What it is1
Vitamin C helps skin make collagen: the enzymes that stabilize the collagen molecule need it.
Pullar JM
Worth knowing5
Some vitamin C can reach the outer layer of skin from a cream or serum, but how well depends on the formula. The skin barrier repels vitamin C, and some gets in only when the product is acidic (below pH 4).
Pullar JMVitamin C products have to keep the molecule from oxidizing and still get it into the skin, which is a real challenge.
Pullar JMIf a person already gets enough vitamin C, a topical product does not appear to raise the amount of vitamin C in their skin.
Pullar JMSome vitamin C derivatives have been shown to reduce melanin production in cultured pigment cells and in living skin.
Pullar JMFor reversing sun damage that has already happened, studies of vitamin C and other antioxidants are hard to interpret.
Pullar JM
Sources
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