The Ordinary 100% L-Ascorbic Acid Powder Unlike with other vitamin C products (whose acid doses are predetermined by the products themselves), this 100% L-Ascorbic Acid Powder ($6) lets you choose how little or much of the active ingredient you'd like to use to treat your dark spots or dullness. It may be a new product at Sephora, but it's already earned a 4.8-star rating from other shoppers. Image Source: sephora.com 100% L-Ascorbic Acid Powder $6 from sephora.com Buy Now