What Ingredients to Avoid in Skincare

When it comes to skincare, consumers are quick to reach for the face cleansers, serums, and moisturizers that promise to satisfy their goals and complement their skin type the fastest and most effectively. (We’ve all been there.) But there’s more to skincare shopping than captivating marketing—it should all start with understanding their almost-always-long list of ingredients, which sometimes happen to include undesirable, superfluous substances. 

Hadley King, M.D., a board-certified dermatologist based in N.Y.C., is here to help decode popular skincare ingredients you may not want to “add to cart.” Supported by studies, the following ingredients have been found to cause skin irritation, acne, or potential health conditions. Keep reading to learn about the ingredients to avoid in skincare.

Table of Contents

    Skincare Ingredients You Should Always Avoid


    “In addition to being a common cause of contact dermatitis—characterized by rashes and blisters—and skin irritation, formaldehyde is also known as a carcinogen,” says Dr. King. Unfortunately formaldehyde, which is used as a preservative to extend shelf life, can be found in many beauty staples, including nail polish, nail polish removers, eyelash glue, and hair straightening products. But it shouldn’t stop at just eliminating formaldehyde—there are also formaldehyde releasers, substances that emit formaldehyde over time to continue the preservation process. “Quaternium-15, DMDM-hydantoin, imidazolidinyl urea, and diazolidinyl urea are all formaldehyde releasers,” shares Dr. King.


    “According to the European Commission’s Scientific Committee on Consumer Products, certain long chain parabens may disrupt the endocrine system and cause reproductive and developmental disorders,” she says of the preservative.


    “Some studies have shown that phthalates can change hormone levels,” says Dr. King. “Phthalates may contribute to endocrine disruption, breast cancer risk, and negatively affect the male reproductive system.” It’s also important to note that due to its low molecular weight, these plasticizers may be absorbed through the skin more easily.  


    Found in everyday essentials like liquid soap and laundry detergent, sulfates—which are favored by companies due to its ability to produce a lather—may cause dry, irritated skin. This may be due to the stripping of the skin’s naturally produced oils.


    While this antimicrobial kills bacteria, fungus, and other microbes, “studies have linked it to a number of different problems including disruption of the endocrine system and the increased risk of cancer,” according to Dr. King.

    Ammonium Chloride

    This ingredient is found in freezing mixtures, batteries, dyes, safety explosives, and in urinary acidifiers and diuretics. “If ingested, it can cause nausea, vomiting, and acidosis in doses of 0.5 to 1 gram,” adds Dr. King. “As with any ammonia compound, concentrated solutions can be irritating to the skin.”

    How to Find the Right Skincare Routine For You

    Now that you know which ingredients to avoid in skincare products, how do you find the right routine for you?! If you’re looking to upgrade your skincare lineup, you’ve come to the right place. Prose just launched a new, Custom Skincare line that takes into account your personal needs. Simply take the consultation to answer questions about your skin, lifestyle, environment, and more. Prose will then match you with custom Cleanser, Serum, and Moisturizer formulas made specifically for you! Take the guesswork out of your skincare routine with Prose.

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