Sodium Lauryl Sulfate

Sodium lauryl sulfate (or SLS) is a synthetic soap-like ingredient that is used in cleansing products such as toothpaste, skin cleansers, shampoos, and soaps, as well as household cleaners and detergents.

SLS is an ingredient that foams well, emulsifies oil into tiny droplets, and dissolves away all oily substances and particulate dirt. Its cleansing properties are so powerful that it is one of the most common ingredients to cause dermal irritation. Stripping the skin of all of its oils can disturb the lipid matrix, thereby leading to skin that is more prone to dryness, cracking, peeling, redness, and irritation.

Scientists and dermatologists actually use SLS when they need to create irritated skin for the purpose of testing new barrier repair or soothing ingredients. It has been noted that some people are more sensitive to SLS than others and that people with pre-existing conditions such as atopic dermatitis tend to be more sensitive.

It is important to note, however, that surface irritation is the only negative effect of SLS. There is no truth to the claims that it is a carcinogenic or otherwise harmful ingredient. It is broken down into completely harmless substances.

SLS is listed among common comedogenic ingredients by acne.org.