Last Updated on September 29, 2020
Sodium Benzoate is a preservative added to some sodas, packaged foods, and personal care products to prolong shelf life. The U.S. Food and Drug Administration (FDA) considers sodium benzoate and benzoic acid to be safe at levels normally consumed by the general public.
Vitamin C is found mostly in fruits and vegetables. Your body needs vitamin C for connective tissue synthesis and immune system function. It's also an antioxidant that protects your cells from damage due to free-radical exposure. Ascorbic acid is one form of vitamin C that's used as a food preservative because its antioxidant properties also protect foods from oxidation when they're exposed to the air.
A large concern over the use of sodium benzoate is its ability to convert to benzene, a known carcinogen.
Benzene can form in soda and other drinks that contain both sodium benzoate and vitamin C (ascorbic acid).
Notably, diet beverages are more prone to benzene formation, as the sugar in regular sodas and fruit drinks may reduce its formation. Other factors, including exposure to heat and light, as well as longer storage periods, can increase benzene levels.
As for sodium benzoate in personal care products, the Environmental Working Group ranks the additive at a hazard level of 3 on a scale of 0 to 10 – meaning that overall risk of its use is relatively low.
The FDA states that exposure to heat and light can stimulate the formation of benzene. So just like any product, skincare that contains ascorbic acid should be stored in a cool, dark place in order to prevent the benzene from forming.