Encyclopedia · surfactant
Sodium lauroyl methyl isethionate
A more soluble cousin of sodium cocoyl isethionate used as a mild cleanser in modern sulfate-free shampoos, with no independent studies of its own.
What it is
SLMI is the N-methyl-substituted lauroyl isethionate. It was designed to dissolve better than sodium cocoyl isethionate and to foam well in clear liquid shampoos.
How it works
It forms mild anionic micelles, similar in principle to SCI. We found no SLMI-specific skin or hair studies in PubMed.
What the studies show
A review gives an overview of shampoo surfactant raw materials and the trend toward sulfate-free systems (Cornwell 2018). We located no peer-reviewed human study of SLMI itself, and the literature on its parent SCI is the closest evidence. Claims about hair feel and dryness come from formulation science and manufacturer material.
Side effects and safety
Expected to be similar to other isethionates, with low irritation. We found no allergy cluster in our search.
Bottom line
A good sign in a sulfate-free shampoo for sensitive or dry scalps, but unproven beyond manufacturer data. Independent mildness and hair-lipid data are missing.
Studies 1
Cornwell PA. A review of shampoo surfactant technology: consumer benefits, raw materials and recent developments. Int J Cosmet Sci. 2018
Result: Overview of shampoo surfactant raw materials, consumer benefits and trends in sulfate-free systems.
Read the study ↗Related
- Sodium cocoyl isethionateA mild anionic cleanser, the basis of many syndet bars, with good lab evidence of being gentle on the skin barrier and growing use in sulfate-free shampoos and shampoo bars.
- Sodium cocoyl glutamateAn amino-acid-based cleanser that was among the best-tolerated surfactants in a 105-patient patch-test study, with no scalp or hair trials yet.