What does Vitamin C do for skin?
Vitamin C and skin
Vitamin C has a genuine, well-understood relationship with skin. It is also the subject of more marketing overreach than any other nutrient, so it is worth separating the two.
The actual mechanism
Skin is largely collagen, and Vitamin C is required to build stable collagen. That is the whole basis of the relationship. It is also why dry, rough or easily damaged skin appears among the signs associated with low Vitamin C — a tissue that turns collagen over constantly shows a shortage early.
Vitamin C also contributes to the protection of cells from oxidative stress, and skin is the tissue most exposed to it.
Taking it and applying it are different things
Topical Vitamin C serums and oral Vitamin C are not interchangeable, and neither substitutes for the other. A serum acts on the skin it is applied to. An oral tablet contributes to whole-body Vitamin C status, of which skin is one beneficiary among many.
A tablet is nutrition. It is not a cosmetic treatment, and Celin does not market it as one.
What to expect, honestly
Correcting a genuine shortfall in a nutrient your skin needs is worth doing. It is not a brightening treatment, an anti-ageing intervention or a fix for a specific skin condition, and anyone selling it as those is ahead of the evidence.
For a skin concern that is bothering you, see a dermatologist.
Nutrient roles throughout this section are per the NIH Office of Dietary Supplements Vitamin C fact sheet for health professionals. Nothing here is medical advice.