Encyclopedia · surfactant
Sodium lauroamphoacetate
The lauric-chain version of the amphoacetate family, used as a mild helper surfactant in sulfate-free shampoos.
What it is
Sodium lauroamphoacetate is the lauric (12-carbon) analogue of sodium cocoamphoacetate. It is used in the same roles: secondary surfactant, foam and mildness.
How it works
Mixing amphoterics with anionics reduces irritation and raises foam stability (Thompson 2023; Cornwell 2018). We found no ingredient-specific mechanism studies.
What the studies show
- In 105 patients patch-tested with eight cleansing surfactants, none caused irritation or allergic reactions at the tested dilution. The best tolerated included disodium cocoamphodiacetate, a related amphoteric (Corazza 2010). It did not test this ingredient.
- A review covers shampoo surfactant raw materials and the move toward sulfate-free systems (Cornwell 2018).
We found no hair-specific human trial for this ingredient, so the direct evidence is weak.
Side effects and safety
Irritation is low for the class, though individual reports of contact allergy to amphoterics exist.
Bottom line
In practice it is interchangeable with sodium cocoamphoacetate. Read the full ingredient list instead of focusing on one co-surfactant. There are no ingredient-specific clinical data.
Studies 3
Corazza M et al. Irritant and sensitizing potential of eight surfactants commonly used in skin cleansers: an evaluation of 105 patients. Dermatitis. 2010
Tested: eight cleansing surfactants
Result: None caused irritation at the tested dilution; best tolerated were sodium cocoyl glutamate, sodium lauroyl oat amino acids and disodium cocoamphodiacetate.
Read the study ↗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 ↗Thompson CJ, Ainger N, Starck P, Mykhaylyk OO, Ryan AJ. Shampoo Science: A Review of the Physiochemical Processes behind the Function of a Shampoo. Macromol Chem Phys. 2023
Result: Reviews how surfactants lift soil from hair (roll-up, emulsification, solubilization), why shampoos pair a primary anionic with an amphoteric co-surfactant, and states that foaming does not affect cleaning. Two authors were from Unilever R&D.
Read the study ↗Related
- Sodium cocoamphoacetateA mild two-charge helper surfactant used in baby, sulfate-free and sensitive-scalp shampoos to soften harsher cleansers.
- Cocamidopropyl betaineThe most common helper surfactant in shampoo, which makes sulfate cleansers gentler, thicker and foamier, and a rare cause of scalp allergy that usually comes from manufacturing impurities.
- Decyl glucosideA plant-derived mild cleanser marketed as ultra-gentle, but its best-documented concern is a rising rate of contact allergy.