When it comes to all-star ingredients in a skincare routine, the roles of vitamin C (or l-ascorbic acid) are wide—just ask literally any dermatologist. With its ability to target signs of aging (like fine lines and wrinkles), and help with brightening, evening-out skin tone, halting melanin production, jump-starting collagen production, and targeting hyperpigmentation/dark spots/sun damage, vitamin C comes with a long list of benefits. But too much of a good thing can exist. In the case of our beloved antioxidant—which helps neutralize free radicals—skin irritation (or what can appear as an allergic reaction) is a potential outcome. That doesn’t mean it will happen to you, but it’s worth opening up the conversation in easy terms to understand. Keep reading for everything to know about topical vitamin C irritation.