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3 Skincare Ingredients That Are Best Avoided

Sometimes there are things that are best avoided. Here are 3 prominent ingredients we would advise you exercise caution with.
Updated: November 9, 2022
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Tens of thousands of ingredients are used to formulate skincare products. While everything that hits store shelves is tested extensively for serious safety issues, sometimes potentially harmful side effects can slip through the cracks. Maybe you’d like to avoid some ingredients altogether to minimize your chances of irritation.

We need to stress that while some ingredients may get a bad wrap online from various places, everyone is different and will process them in their own way. Experiences are subjective, so keep that in mind while we provide the following information.

Here are some ingredients that may cause some issues.

Sodium Lauryl Sulfate

This ingredient is used in a variety of cosmetics and cleaning products. It’s a common cleansing agent and can be found in grooming, haircare, bath, and dental products. According to the FDA, it is perfectly safe [1] but if overused it can cause irritation and discomfort. There are currently no links to serious illness or other more damaging health issues.

You’ll probably be fine using products containing sodium lauryl sulfate, but if you want to avoid it there are more and more products appearing on the market that don’t include it in their formula.


Methylisothiazolinone is a preservative that is commonly found in cleansers and shampoos. The concentration of this ingredient in products is regulated by the FDA in the United States, as it can cause sensations of burning, rashes, and in some cases even breakouts of hives. According to the US Environmental Protection Agency, Methylisothiazolinone has been shown to have “moderate acute toxicity by the oral and inhalation routes. It is highly acutely toxic when applied dermally or to the eye and is considered to be corrosive.” [2]

Take care when using products containing Methylisothiazolinone. There are alternatives available.


Perhaps one of the more infamous ingredients in cosmetics is Formaldehyde. It is found in preservatives that are often inserted into skincare products. Unfortunately, Formaldehyde can cause irritation of the skin, nose, eyes, and throat. Furthermore, according to the US Environmental Protection Agency, high levels of exposure can cause some types of cancers [3]. Not nice, right?

Once again, always read the ingredients label before using a product and evaluate your own personal risk.


The skincare and cosmetics industry is generally very safe, however, if you have particularly sensitive skin or other conditions, you may want to be careful with your product choices.

We’d like to stress that we are not medical professionals, and if you have any specific health concerns you should always consult your doctor.

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This article has been reviewed by the in-field experts on our Medical Content Advisory Board to ensure everything is up-to-date and accurate.