Sodium Cocoyl Isethionate vs Sodium Lauryl Sulfate: which is worse?

What is Sodium Cocoyl Isethionate?

Sodium cocoyl isethionate is a mild anionic surfactant derived from coconut fatty acids and isethionic acid. It exists as a solid powder and produces a creamy, conditioning lather that leaves skin feeling soft. It is the primary surfactant in most syndet (synthetic detergent) bars.

What is Sodium Lauryl Sulfate?

Sodium lauryl sulfate is an anionic surfactant derived from lauryl alcohol (from coconut or palm oil). It is one of the oldest and most-studied cosmetic surfactants, prized for its powerful foaming and degreasing properties. Unlike SLES, it is not ethoxylated.

Documented risks

Sodium Cocoyl Isethionate: Sodium cocoyl isethionate has an excellent safety record. It is one of the surfactants recommended by the National Eczema Association for sensitive and atopic skin. No carcinogenic, mutagenic, or endocrine-disrupting effects are known. Potential contact sensitization is extremely rare. It performs well at physiological pH, minimizing skin barrier disruption.

Sodium Lauryl Sulfate: SLS is safe at cosmetic use concentrations per the CIR Expert Panel. It is more irritating than SLES to skin and mucous membranes, particularly at concentrations above 2% with prolonged contact; this is why most rinse-off products keep it at 1–2% or opt for SLES. It can disrupt the skin barrier transiently, which is why some people with canker sores or eczema avoid SLS toothpastes and cleansers. It is not carcinogenic, not a hormone disruptor, and is not absorbed systemically in meaningful amounts. It biodegrades rapidly in the environment.