3 Ingredient Combos You Should Never Put on Your Skin

Most skin-care routines are composed of a cocktail of ingredients. We start with squirt of this, a scoop of that, and by the end we’ve layered a myriad of products in hopes of perfecting our complexion. That “the more, the merrier” saying seems fitting for moments like this, but the layers you’ve sworn by aren’t always compatible with one another.

If you’re not using a unified collection of products (which most of us don’t), experts say it’s important to look at what active ingredients are in each product to ensure you aren’t overdoing it. If you don’t, this will likely lead to irritated or inflamed skin.

“Usually things that are already combined together in a bottle will work well together because they are specifically mixed with proper amounts of each concentration,” shares cosmetic physician Stanley Kovak, MD. “However, if you use two or more separate bottles, the product in each might have the wrong concentration and can give you unwanted side effects.”

Here are ingredients that should not mingle together at your next skin-care soiree.

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Retinol & Glycolic Acid

If your skin goal is to brighten and illuminate your complexion or clear pesky breakouts, you’ve probably been told that retinol and glycolic acids get the job done. While both are indeed powerhouse ingredients, using them together can actually be quite drying to the skin. “When too much of these ingredients is placed on the skin, it can cause dryness and sensitivity to sunlight,” warns Dr. Kovak. Having one product that causes dryness and tightness is annoying enough, but when you double up, skin becomes irritated and desperate for moisture.

If you don’t want to let one of these ingredients go, adjust your skin-care routine to use one at morning and one in the evening. In this case, opt for the glycolic acid in the morning and the retinol in the evening, as sunlight can deactivate retinol. This solution allows you to keep both active ingredients in your regimen without stripping the skin.

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Retinol & Benzoyl Peroxide

Retinol has long been regarded as a solution to many skin-care concerns, from dark spots to texture and tone. But this super-ingredient doesn’t always play nice with the other products in your beauty arsenal. “Most retinols dry out the skin, so when combined with a further drying agent like benzoyl peroxide or high alcohol content, the retinol will irritate the skin more than normal,” shares Suneel Chilukuri, MD, a Houston-based dermatologist.

“As a result, patients may notice worsening of acne, eczema, or psoriasis when combining these ingredients.” If you’re going to mix your retinol at all, Dr. Chilukuri recommends using a moisturizer before applying it to allow for deeper penetration into the skin and protect from superficial skin irritations.

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Vitamin C & H20

Vitamin C is a great pick for an overall complexion booster, with benefits from lightening dark spots to imparting an overall brighter complexion. It’s full of antioxidants, but in order to reap the benefits, the molecule has to be stable. “Vitamin C is an unstable molecule and oxidizes quickly,” shares Dr. Chilukuri.

“Most manufacturers will add vitamin E to stabilize the vitamin C molecule or keep its beauty benefits when applied, but water destabilizes it.” In other words, in order to ensure your skin is receiving the antioxidant benefits of the vitamin C, the vitamin cannot oxidize, which causes it to become unstable.

Rule of thumb: If your ingredients are foes, but you don’t want to part with them, keep them separate.