Sodium Benzoate

Preservative that inhibits the growth of bacteria, mold, and yeast. Sodium Benzoate functions as a broad-spectrum antimicrobial preservative in cosmetic formulations. Its efficacy relies on its conversion to benzoic acid in acidic environments (pH < 4.5). Benzoic acid, being lipophilic, readily penetrates microbial cell membranes. Once inside the cell, it dissociates, acidifying the intracellular environment and inhibiting crucial microbial enzyme systems, such as those involved in oxidative phosphorylation and glucose uptake. This disruption of intracellular pH and metabolic processes effectively inhibits the growth of yeasts, molds, and some bacteria, thereby preventing product spoilage and potential microbial contamination on the skin.

The CIR Expert Panel has concluded Sodium Benzoate is safe as a cosmetic ingredient in the present practices of use and concentration. It is generally recognized as safe (GRAS) by the FDA as a food additive. While generally well-tolerated, rare cases of contact urticaria or allergic reactions have been reported, primarily in individuals with pre-existing sensitivities.

Look for products with 0.1-1.0% (most formulas use 0.1-0.5%). The EU's maximum permitted concentration as benzoic acid is 0.5% in rinse-off and leave-on products, except for mouthwash where it is 1.7%. for clinical efficacy.