It's important to note that, while it is suitable for most skin types, it is a powerful antioxidant and shouldn't be overused and that there are some people who could be allergic to

it. You might also experience some sensitivity when you start using the product. "It is a good idea to use very small amounts and not to use the product every day when you first begin to get your skin sensitized and to ensure you are not in the small group of people who may be allergic. Itching, redness, sensitivity, and tingling are symptoms of an allergy to vitamin C," explains board-certified dermatologist Jason Emer, MD, FAAD, who has his own vitamin C product, Aox-C ($165).

He does add that, if you have oily skin, you might want to proceed with caution, as the base of the product might make your skin more oily.