surfactantWell-Known
Sodium Lauryl Sulfate (SLS)
Also known as: Sodium Dodecyl Sulfate
Medically reviewed by ChokChok · Updated April 15, 2026
The foaming surfactant that earned its villain status through sheer harshness — not because it's toxic, but because it genuinely strips skin.
What It Does
CleanserFoaming agent
Deep Dive
SLS is a strong anionic surfactant that's efficient at removing oil and creating foam, but its aggressive action disrupts the skin barrier. Used for decades as the industry standard foaming cleanser base, it's been largely replaced in skincare by gentler amphoteric (cocamidopropyl betaine) and nonionic (decyl glucoside) surfactants. SLS is still common in budget cleansers and shampoos. Not dangerous, just harsh. SLES (sodium laureth sulfate) is a milder ethoxylated version.
Not Ideal For
SensitiveDry
Effective Concentration
Commonly 5–20% in cleansers and shampoos.