INCI: sodium benzoate
What is sodium benzoate?
The sodium salt of benzoic acid. A common preservative used in skincare and cosmetics.
Sodium benzoate and benzoic acid are naturally found in many foods such as cranberries, plums, cinnamon, apples, milk, cheese, and yogurt.
It comes as a white crystalline solid that can easily dissolve in water to form a transparent liquid.
Use & Benefits:
As a preservative, it is able to prevent bacterial and fungal growth in cosmetic products. The microorganism absorbs benzoic acid causes the ph to drop, causing the enzymatic function to decrease inhibiting the reproductivity of the organism.
Sodium benzoate is considered safe for use in cosmetics, although when combined with Vitamin C in a formulation, a chemical reaction occurs, causing the formation of benzene. Benzene is a known carcinogen; however, there are ways to formulate a product with both ingredients preventing that chemical reaction. This could be using sodium benzoate at a low concentration and vitamin C at a very concentration this due to vitamin acting as a free radical scavenger instead of reacting with sodium benzoate.
Another concern is that sodium benzoate damages cells by increasing the production of free radicals. Free radicals are very unstable and will damage cell membranes, DNA, and proteins.