How to use the hero ingredient when your skin is reactive.

What causes sensitive skin? Less of a medical diagnosis and more of a complaint, sensitive skin is essentially any skin that is unable to tolerate chemicals, environments, harsh conditions or even certain foods. It can be set off by the weather, hormones or sleep deprivation. Exposure to any of these can result in burning, stinging, redness or just discomfort. What’s happening is that the nerve endings in the top layer of the skin get aggravated, which is often due to a weakened skin barrier. Certain harsh products can also just be too much. Detergents, soaps, dyes and fragrances can cause itchiness, redness and dryness. What’s more, sensitive skin can be classified in different types. It can simply be genetic and associated with inflammatory conditions like eczema, psoriasis and rosacea. It can be environmentally sensitive, set off by the sun or pollution. It can be reactive, triggered by certain skincare ingredients. Or it’s just thin skin, which happens with age and makes irritation more common.

What is vitamin C?

Vitamin C is a potent antioxidant—which we cannot produce on our own—capable of neutralizing free radicals that are brought on by UV exposure and pollution. Because of that, it helps with skin’s own regeneration process, aiding in repairing damaged skin cells. As a result, signs of aging are warded off.

Why is vitamin C good for skin?

Beyond how vitamin C can disarm free radicals—even more so when it’s layered under your sunscreen—it has an astounding amount of additional benefits. It accelerates the production of collagen and elastin, the naturally occurring protein fibers that keep skin plump like a toddler’s cheeks; it can lighten hyperpigmentation by blocking the pathway of pigment synthesis so it has an overall brightening effect; and it can help with acne because of its anti-inflammatory properties. However, it is also highly acidic—this is what triggers the skin to heal itself and make collagen and elastin—so it can be irritating to those with sensitive skin. Choose a vitamin C for sensitive skin product such as SkinCeuticals Serum 10 AOX+. With 10% vitamin C, Serum 10 AOX+ is a lower concentration that is better tolerated and has an acidic pH range between 2.0 and 3.5. Try a patch area first to see how you make out.

What not to mix with vitamin C

While vitamin C is generally well tolerated, if you have sensitive skin, it may sting a bit if you use it after an exfoliating scrub or acid. Steer clear of benzoyl peroxide (it will oxidize the vitamin C) or any other harsh topical creams such as ones with retinol and AHAs; these are just too active a combination and will result in redness and irritation. You should also avoid niacinamide, as it will cancel out vitamin C chemically. Another important tip? If you’re pregnant or breastfeeding, avoid skincare products with salicylic acid.