Sodium Lauryl Sulfate (SLS) and Sodium Laureth Sulfate (SLES)

Sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES) are surfactants, a type of ingredient that helps water mix with oil and grease so they can be lifted and washed away. SLS and SLES are similar ingredients and are both effective at cleaning surfaces and creating foam. One key difference is that SLES is made using a process called ethoxylation. Ethoxylation changes the properties of the surfactant, which can help it feel gentler on skin compared to SLS. Both SLS and SLES are commonly used in products like shampoos, body washes, and hand soaps, as well as household cleaners such as dish soaps and toilet bowl cleaners.

 

Are there concerns associated with SLS and SLES?

Both SLS and SLES can be corrosive to the eyes and irritating to skin. However, these concerns typically arise only at concentrations that are higher than what is found in consumer products, or with prolonged exposure. Because SLS and SLES are effective at removing oils, they may also contribute to skin dryness for some users, especially those with sensitive skin. In products with intended skin contact, they are commonly combined with conditioning or moisturizing ingredients to help reduce irritation.

SLS and SLES have been reviewed by the Expert Panel for Cosmetic Ingredient Safety and European Chemicals Agency (ECHA). They are considered acceptable to use in personal care products, though people with sensitive skin may choose to avoid products that contain them.

SLS and SLES are considered biodegradable consistent with EU Regulation and are not persistent in the environment, though they may be harmful to aquatic life at high concentrations. SLES can contain trace amounts of 1,4-dioxane  from the ethoxylation process. 1,4-dioxane has been identified as a possible human carcinogen and can persist in the environment. Because of these concerns, it is included on our Restricted Use Materials list. We apply strict internal limits, working closely with our suppliers to carefully restrict any trace amounts of remaining 1,4-dioxane.

Depending on the product type and use application, other surfactant alternatives to SLS and SLES include linear alkylbenzene sulfonates, alpha olefin sulfonates, alkyl isethionates, taurates, and sulfonated methyl esters. Like many surfactants, these alternatives may also be irritating to skin and harmful to aquatic life in high concentrations.

References: Sodium Lauryl Sulfate (SLS) - Chemical Safety Facts;   Human and Environmental Toxicity of Sodium Lauryl Sulfate (SLS): Evidence for Safe Use in Household Cleaning Products ;  CIR SLS and SLES Ingredient Review ;  Safer Detergents and Surfactants for EU consumers