Sodium Laureth Sulfate.

What it does

It is the ethoxylated cousin of SLS: a bigger water-soluble head makes it noticeably milder and less irritating, while still lifting away oil and dirt and producing a generous (if airy) lather. It is a cleansing agent, not a leave-on skin active.

Benefits

• Effective, inexpensive foaming cleanser that removes oil and grime well
• Milder and much less irritating than SLS thanks to its larger water-soluble head group
• Produces a rich, easy lather that gives cleansers a pleasant feel
• Generally considered safe at the levels used in rinse-off cosmetics

Side effects

• Classified as a skin and eye irritant; can be drying or irritating for some people, especially on the face
• Sits in the middle for mildness, so very sensitive or dry skin may prefer gentler facial cleansers
• Manufacturing can leave trace 1,4-dioxane, a probable carcinogen, though reputable makers strip it out via vacuum/steam purification

Who it's for

Normal to oily skin and general body cleansing where good foam and a thorough clean are wanted