With the list of “must-have” skin-care products growing by the minute, the list of ingredients you’re putting on your skin is growing, too. It’s no surprise that some just don’t go together. Here, David Colbert, M.D., a New York City-based dermatologist, points out which combinations you should always avoid.
1. Vitamin C and Benzoyl Peroxide
Benzoyl peroxide is an acne-clearing staple in many people’s skin-care routines. Enter vitamin C, the trendy new kid in town that every dermatologist seems to be recommending. While you totally can (and should!) add vitamin C to your routine, Colbert warns not to use it with benzoyl peroxide. The topical treatment will oxidize the vitamin C, rendering the effects of both useless. Only use one on days you won’t be using the other.
2. Salicylic Acid and Glycolic Acid
All acids are not created equal, and they all don’t have the same effects on your skin. Salicylic acid is an acne treatment, and glycolic acid is an exfoliator that removes dead skin without your having to scrub away at it. Both are great ingredients, but when used together, they can seriously dry out your skin, says Colbert. Again, only use one at a time.
3. Retin-A and Gritty Exfoliants
Retin-A is an ingredient seriously loved by dermatologist for its ability to help skin renew itself; it helps treat wrinkles, discoloration, and overall roughness. Unfortunately, Retin-A has a tendency to dry out skin, causing it to peel. What better way to get rid of dry skin than removing it with an exfoliator, right? Wrong. Retin-A makes skin super-sensitive, and rubbing gritty exfoliants against it will only make the situation worse, says Colbert. Try a cleansing with a muslin cloth, which is a gentle way to buff away dead skin.
4. Sonic Brush and Exfoliants
When sonic brushes came on the scene, they were praised for their gentle exfoliation capabilities. But old habits die hard, and you may still have an exfoliator in your routine. If so, it’s time to let go, says Colbert. You may be exfoliating too much, stripping your face of healthy oils, and roughing up your skin. It’s either one or the other—you choose.
5. Retin-A and Toner
Toners are great for a multitude of reasons; some have glycolic acid that brings new skin to the surface, some contain witch hazel, which is great at treating acne. But when Retin-A is in your routine, Colbert warns against using them. “You wouldn’t want to use them together over your whole face, otherwise it will dry our your skin,” he says. Pick your favorite, and stick with it.