Final Report of the Safety Assessment of Lithium Stearate, Aluminum Distearate, Aluminum Stearate, Aluminum Tristearate, Ammonium Stearate, Calcium Stearate, Magnesium Stearate, Potassium Stearate, Sodium Stearate, and Zinc Stearate

Abstract

The commercial grade of stearic acid used in cosmetics contains fatty acids that range from C18 (stearic) and C22 (behenic). The concentrations of these ingredients used in cosmetic products vary from ≤ 0.1 to > 50%. Acute oral studies with rats indicated that the Stearates are practically nontoxic, and have a low potential for acute dermal toxicity. Skin irritation studies with rabbits demonstrated that Stearates are only minimal to slight irritants at high concentrations. Pharmaceutical vehicles containing 5.5% Magnesium Stearate were neither teratogenic nor mutagenic. In a limited study, Stearate did not increase bladder tumor incidence. Seven out of 20 subjects exhibited minimal to mild skin erythema when tested with an aqueous solution of 1.5% Ammonium Stearate. Similar results were obtained with Sodium Stearate at 0.5 percent. In a 21-day patch test with 10 subjects, an aqueous formulation containing 0.1-0.25% Sodium Stearate caused minimal skin irritation. No sensitization was reported in 100 subjects tested with the same formulation. On the basis of the available information presented in this report, and as qualified in the summary, it is concluded that the Stearate compounds described herein are safe as cosmetic ingredients.