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

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

SLS is what’s known as a “surfactant.” This means it lowers the surface tension between ingredients, which is why it’s used as a cleansing and foaming agent.

Most concerns about SLS stem from the fact that it can be found in beauty and self-care products as well as in household cleaners.

Sodium laureth sulfate (SLES) is a surfactant with a similar chemical formula. However, SLES is milder and less irritating than SLS.

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 used in a variety of products, including:

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

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

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

The Food and Drug Administration (FDA) regards SLS as safe as a food additive.

Regarding its use in cosmetics and body products, the safety assessment study of SLS, published in 1983 in the International Journal of Toxicology (the most recent assessment), found that it’s not harmful if used briefly and rinsed from the skin, as with shampoos and soaps.

The report says that products that stay on the skin longer shouldn’t exceed 1 percent concentration of SLS.

However, the same assessment did suggest some possible, albeit minimal, risk to humans using SLS. For example, some tests 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.

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

According to a 2015 study, SLS is safe for use in household cleaning products.

The amount of SLS found in your personal care products is limited in concentration. 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 online or at stores by reviewing the ingredient labels.