are your skin-care products destroying each other?

Day and night, you strive to be the devout skin caretaker your grandmother always wanted you to be. You cleanse, tone, treat, moisturize, and protect with sunscreen (right?!). But some of your products may render each other less effective or even cause damage. Not only are you doing your skin a disservice, it is literally absorbing costs. 

Many popular ingredients—such as retinol, vitamin C, and exfoliating acids—don’t perform at their maximum effectiveness if you use them together. Certain mixtures can cause severe dryness, irritability, inflammation, and even burning, hindering your skin’s ability to look and feel its happiest.

Don’t be daunted just yet—we have two skin experts on board to help sift through all the confusing information: Celebrity aesthetician Renee Rouleau, who’s responsible for the luminous complexions of Sofia Vergara and Demi Lovato, and Dr. Carl Thornfeldt, a straight-to-the-facts dermatologist and founder of Epionce Skincare. 

Whether it’s instant irritation or two products competing on your skin, make sure you’re attentive about what you feed your face. Click through the gallery to see which ingredients you shouldn't be using at the same time. Glow on!

Retinols + Benzoyl PeroxideThese two ingredients have been shown to deactivate each other when they’re used together, according to Rouleau, who adds that “side effects could include peeling, redness, increased pigment and discoloration, and burning of the skin.” Dr. Thornfeldt says, “Benzoyl peroxide will damage pretty much any other anti-aging product out there.”

Alpha Hydroxy Acids (AHAs) + RetinolsFlashback to chem class. AHAs, such as glycolic acid, prefer a pH level of two, while retinols like a pH level of five. Without getting too science-y, this means they’re not exactly two peas in a pod when it comes to delivering the best results. Dr. Thornfeldt says, “There are ways around it, but chemically, it’s very difficult to do. “Although it can’t be said that all AHA and retinol combos don’t work well together, stay on the safe side. Rouleau says, “Each of these ingredients serve a different purpose, so I recommend alternating nights when using them separately to get the full benefit of each.”

Vitamin C + AHAsBoth these ingredients are acid-based, and by using them at the same time, you’re overloading your skin with acids, significantly increasing your chances of redness, peeling, and irritation. Plus, Dr. Thornfeldt says, “Applying massive amounts of one or two acids won’t provide long-lasting, significant benefits.” Rouleau advises, “Vitamin C is best reserved for daytime use because of its ability to lessen daily oxidative stress from the environment, whereas AHAs are more for skin repair and are most effective when used at night.” 

Salicylic Acid + RetinolsThis combo might cause skin to become inflamed, ruddy, and dry. Rouleau says, “Retinol stimulates cell turnover and generates new collagen from deep within the skin, while acids work to exfoliate on the surface. These products have amazing benefits, but using them together can be too irritating and could cause redness, peeling, and possible burning of the skin.”

Citric AcidThis is a tricky one. Rouleau tells us citric acid is typically included just to adjust the pH of products. However, layering it with other products might cause irritation. Dr. Thornfeldt notes citric acid is known to cause allergic contact reactions in some people. If you have sensitive skin, consult a professional before using!

BONUS TIP! Don’t cocktail serums and moisturizers: As an extra precaution, our experts recommend you layer these two product types, as opposed to mixing them in your hand before you apply them (a tempting time saver). If you do mix them, as Rouleau tells us, “they are now diluted and [each] can’t deliver the full benefit.” You paid a pretty penny for your skin care, and you deserve to reap 100 percent of the benefits.