As a preservative, sodium benzoate is primarily an anti-fungal agent but also has some effectiveness against bacteria. It is soluble in water where it converts to benzoic acid, its active form, at a low pH. Benzoic acid is very pH dependent being most active at pH 3 (94%).
Sodium benzoate is used in a wide variety of cosmetics and personal care products where it acts as a corrosion inhibitor, fragrance ingredient besides being a preservative.
Sodium Benzoate is often combined with Potassium Sorbate in low pH products to provide a synergistic preservative effect against yeast and mold.
INCI: Sodium Benzoate
Usage Rate: 1%