"It can take your skin some time to tolerate high percentages of vitamin C," Dr. Goldberg explained. "When you first start using it, it can cause tingling and slight redness until your skin gets used to the ingredient."
He recommended starting with a lower percentage and working your way up to higher concentrations or sticking with the lower percentage if you have very sensitive skin. A gentle, but effective, introductory product is Mario Badescu Vitamin C Serum ($45). It delivers a 7.5 percent vitamin C concentration that noticeably brightens the skin, reduces pore size, and corrects discoloration. Because it contains aloe leaf juice, cucumber extract, and ginseng root extract, it also helps soothe irritated, angry skin, while hyaluronic acid and collagen plump and improve elasticity.