While there is certainly proof that vitamins taken orally make their way to the skin, there are times when you may see more benefits by applying them where you want them to work.
Take vitamin A, for example, which is the main ingredient in over-the-counter retinols and prescription retinoids. When applies topically, vitamin A-based products can dramatically change the appearance of the skin; but that can’t be said for vitamin A supplements. However, some doctors believe that some vitamins, like C, better benefits the skin when taken orally because its effectiveness degrades rapidly with light exposure.
Your best bet: launch a dual attack by augmenting your topical beauty regimen with a nutritious diet and a multivitamin or specialty supplement.