It’s one of the ingredients you’ll find on your shampoo bottle. But unless you’re a chemist, you likely don’t know what it means. Sodium lauryl sulfate (SLS) is a chemical found in many cleaning and beauty products, but it’s frequently misunderstood.

Urban myths have linked it to cancer, skin irritation, and more. But science may tell a different story.

SLS is what’s called a “surfactant.” This means it lowers the surface tension between ingredients, which is why it’s used as a cleansing and foaming agent. Most concern surrounding SLS stems from the fact that it can be found in beauty and self-care products as well as in household cleaners.

If you look under your bathroom sink, or on the shelf in your shower, it’s very likely you’ll find SLS in your home. It’s found in a variety of products including:

  • Grooming products, such as shaving cream, lip balm, hand sanitizer, nail treatments, make-up remover, foundation, facial cleansers, exfoliants, and liquid hand soap.
  • Hair products, like hair coloring, dandruff treatment, and styling gel.
  • Dental care products, such as toothpaste, teeth whitening products, and mouthwash.
  • Bath products, like shampoo, conditioner, bath oils and salts, body wash, and bubble bath.
  • Creams and lotions, such as hand cream, masks, anti-itch creams, depilatory preparations, and sunscreen.

You’ll notice that all of these products are topical, or applied directly to the skin.

SLS is also used as a food additive, usually as an emulsifier or thickener. It can be found in dried egg products, some marshmallow products, and certain dry beverage bases.

The U.S. Food and Drug Administration (FDA) regards SLS as safe. A safety assessment study of sodium lauryl sulfate found that it’s not harmful if used briefly and rinsed from the skin, as with shampoos and soaps. Products that stay on the skin longer shouldn’t exceed 1% concentration of SLS.

However, the same assessment did suggest some possible, albeit minimal, risk to humans using SLS. For example, a study they reviewed found that continuous skin exposure to SLS could cause mild to moderate irritation in animals.

Nevertheless, the assessment concluded that SLS is safe in formulations used in cosmetics and personal care products. Because many of these products are designed to be rinsed off after short applications, the risks are minimal.

Sodium lauryl sulfate consumption has not been studied in humans.

But, What About Cancer?

According to most research, while SLS is an irritant it is not a carcinogen. Studies have shown no link between the use of SLS and increased cancer risk.

The amount of SLS found in your personal care products is limited in concentration. But for people who simply don’t believe that SLS is safe, or don’t want to try their luck, an increasing number of products that don’t contain SLS are appearing on the market. Look for them on the web or at stores by reviewing the ingredient labels.