Sodium Lauryl Sulfate
Strong anionic surfactant. Cleans well, but on facial skin it strips the barrier faster than gentler alternatives.
What it does
Sodium lauryl sulfate is the workhorse cleanser of mid-century soap chemistry — high foam, low cost, very effective at removing oil. It's also a well-documented skin irritant in patch testing, used in research as the standard barrier-disruption agent. SLS in body wash or shampoo passes by quickly; SLS as the primary surfactant in a face cleanser is the formulation choice that most often produces 'this cleanser leaves my skin tight.' Newer face cleansers prefer milder surfactants like sodium cocoyl isethionate or glucosides.
The evidence, graded
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
Also known as
sls