Ammonium Lauryl Sulfate vs Sodium Laureth Sulfate: which is worse?

What is Ammonium Lauryl Sulfate?

Ammonium lauryl sulfate is an anionic surfactant analogous to SLS but with an ammonium cation. It provides strong foaming and cleansing. It is slightly more water-soluble than SLS.

What is Sodium Laureth Sulfate?

Sodium laureth sulfate (SLES) is an anionic surfactant derived from ethoxylated lauryl alcohol, widely used as a primary lathering and cleansing agent. It is milder than its close relative SLS because the ethoxylation process reduces skin irritation potential. SLES is one of the most common cosmetic surfactants globally.

Documented risks

Ammonium Lauryl Sulfate: ALS is slightly more irritating than ALES and comparable to SLS at equivalent concentrations. At typical shampoo concentrations (2–10%), it is considered safe by the CIR. It is not carcinogenic, not a hormone disruptor, and does not accumulate in body tissues. Prolonged skin contact at high concentrations can cause irritation; this is not a concern in rinse-off applications.

Sodium Laureth Sulfate: SLES is broadly considered safe at cosmetic use levels (typically 1–20%). The Cosmetic Ingredient Review (CIR) Expert Panel concluded it is safe as used in rinse-off products. A known manufacturing byproduct, 1,4-dioxane, can appear at trace levels; reputable manufacturers use vacuum-stripping to minimize it below regulatory limits. SLES does not penetrate intact skin significantly and is not a carcinogen or systemic toxin. Some individuals with very sensitive or eczema-prone skin may experience mild irritation at higher concentrations; this resolves upon rinsing. It is not a hormone disruptor and does not accumulate in the body.