7 Final Report on the Safety Assessment of Sodium Lauryl Sulfate and Ammonium Lauryl Sulfate

Abstract

Sodium and Ammonium Lauryl Sulfate are anionic surfactants used in cosmetics as cleansing agents. In absorption, metabolism, and excretion studies, Sodium Lauryl Sulfate had a degenerative effect on the cell membranes because of its protein denaturing properties. Low levels of skin penetration may occur at high use concentration. Sodium Lauryl Sulfate had an LD50 of 0.8 to 1.10 g/kg in rats. A formulation containing 15% Ammonium Lauryl Sulfate caused depression, labored breathing, diarrhea, and death in four out of 20 animals. In acute ocular tests, 10% Sodium Lauryl Sulfate caused corneal damage to the rabbits' eyes if not irrigated, or if irrigation was delayed. A Draize test of a product containing 5.1% Sodium Lauryl Sulfate caused mild irritation, and products containing 21% detergent were severely irritating with no rinse, and mildly irritating when rinsed. Ammonium Lauryl Sulfate solutions containing 1.25%-27.4% detergent showed increasing irritation with increasing concentration; rinsing decreased irritation. Acute animal skin irritation studies of 0.5%-10% Sodium Lauryl Sulfate caused slight to moderate irritation. Applications of 10%-30% detergent caused skin corrosion and severe irritation. Solutions of 2%, 10%, and 20% Ammonium Lauryl Sulfate were highly irritating and dangerous. One percent and 5% Sodium Lauryl Sulfate produced a significant number of comedones when applied to the pinna of albino rabbits. A chronic oral feeding study in rats of 0.25%, 0.5%, and 1.0% Sodium Lauryl Sulfate in the diet for two years produced no abnormalities. A 91-day percutaneous toxicity study of a shampoo containing 17.5% Ammonium Lauryl Sulfate had no treatment-related abnormalities except for moderate to severe dermal effects. In mutagenesis studies, rats fed 1.13% and 0.56% Sodium Lauryl Sulfate in the diet for 90 days produced no more chromosomal aberrations or clastogenic effects than did a control diet. Sodium Lauryl Sulfate was tested for human skin irritation in concentrations ranging from 0.1 % to 10%. Open patches were less irritating than closed patches, and irritation increased directly with concentration. Similar results were obtained when formulations containing Sodium and Ammonium Lauryl Sulfate were tested. No UV light sensitization occurred from any formulation in this latter study. Both Sodium and Ammonium Lauryl Sulfate appear to be safe in formulations designed for discontinuous, brief use followed by thorough rinsing from the surface of the skin. In products intended for prolonged contact with skin, concentrations should not exceed 1%.