What is Sodium Lauryl Sulfate, and why is it used?
A strong cleansing and foaming surfactant in shampoos and toothpastes. Related to the milder SLES.
Why it's used
Lifts oil and dirt and creates foam.
Known concern
Can irritate skin with longer or concentrated contact — dermatology research uses it as a standard irritant.
Exposure context
In rinse-off products the contact is brief and diluted. Expert review concluded it is safe in rinse-off products and at low levels in leave-on products.
Evidence & sources
SLS is safe in brief, rinse-off use; leave-on use should be limited to low concentrations. Evidence: regulatory. Known: Concentration and contact time drive irritation. Unknown: Individual sensitivity varies. Source: Cosmetic Ingredient Review (CIR), Final Report on the Safety Assessment of Sodium Lauryl Sulfate (1983, re-reviewed since).