Are There Any Skin Care Ingredients You Shouldn’t Mix?

If you’re dealing with multiple skin concerns, your instinct may be to use as many skin care actives as you can, as often as you can, to achieve your goals. But following that urge can have some not-so-pleasant consequences, especially if you’re combining ingredients that are meant to be used on their own. As it turns out, there are several popular ingredients that perform better solo than as part of an ensemble cast.

Retinol — and its many related compounds — is a prime example of a skin care ingredient you should use on its own. This vitamin A derivative can smooth wrinkles, firm the skin, and banish breakouts, but it can be pretty drying (especially in higher concentrations). Combining it with other ingredients that can dry out your skin, such as benzoyl peroxide, can make those side effects worse. Experts also advise against using chemical exfoliants (AHAs and BHAs) at the same time as retinol, as both accelerate skin cell turnover. Using them together could disrupt your skin barrier and leave you with a red, irritated complexion.

Not all ingredient pairings are so dire, though. In some cases, combining certain ingredients is just a waste. Benzoyl peroxide, for example, oxidizes upon contact with the skin. Pairing it with vitamin C — an antioxidant — vastly reduces the efficacy of the latter, per Dr. Whitney Bowe. Using these two ingredients together is unlikely to harm your skin — but it won’t help it, either. 

If you do want to use multiple actives, the best approach is to use one in the morning and the other in the evening, or on alternate days. This could mean using an exfoliating serum in the morning and retinol at night, or applying a retinol cream every other night, with an AHA product on the days between. If you’re ever unsure how or when to use your skin care products, we suggest consulting a dermatologist. They’ll be able to provide specific advice pertinent to your skin so you can address your skin concerns safely.