Layering skincare products can make each of the active ingredients you use more effective. Or, it can do the exact opposite. Certain combinations just don’t play nicely together, and when two ingredients clash, your skin ends up paying the price. Not only can it lead to multiple days' worth of irritation, but it could go so far as to cause burns.
To make sure you’re never caught up in the aftermath of product layering gone wrong, we called in Dr. Kraffert, board certified dermatologist and president of Amarte. He gave us the all of the information on the combinations to be avoided at all costs.
“Decreased tolerability is a concern whenever exfoliants (physical or chemical) are combined,” Dr. Kraffert says. Because beta hydroxy acids, like salicylic acid, and benzoyl peroxide are both exfoliating ingredients, you run the risk of irritating your skin. Keep the two separate to prevent redness and peeling. It's already a hotly debated topic whether benzoyl peroxide is safe to use on its own; adding a harsher product on top of it isn't going to be good for you.
When layering vitamin C, you have to look out for active ingredient neutralization because antioxidants, like vitamin C, are inherently unstable. “Vitamin C is very pH sensitive, and mixing it with AHAs tends to substantially diminish its delivery within the skin,” Dr. Kraffert says. Powerful alpha hydroxy acids actually alter the pH level of vitamin C, which degrades its antioxidant properties. The combination also might irritate your skin—particularly if you're sensitive to Vitamin C, which many people are.
Dr. Kraffert says there are a number of issues at play when combining AHAs or BHAs and retinoids. First, there’s the significantly increased potential for irritation that comes with combining exfoliating acids (like gylcolic, lactic, and salicylic) with retinoids. And then, there’s also the matter of ingredient deactivation. Like vitamin C, retinol can be somewhat unstable. Alpha hydroxy acid oxidizes it, making it less effective. So, you could (or if you're at all sensitive to retinol, will) end up with aggravated skin that’s not even reaping the benefits of your products.
Perhaps this goes without saying, but we'll say it anyway: Don’t layer multiple retinols. It probably won't end well. To avoid inflaming your skin, use only one at a time. You’ll do more harm than good if you apply a retinol serum and top it off with retinol cream. You also might end up with a face that's itchy for days. “This includes taking care not to use your facial retinoids on the delicate eye area, followed by your retinol eye cream,” Dr. Kraffert says. The eye area is an easy spot to overdo it—be mindful of the active ingredients in your eye creams.