What is it?
A simple aromatic acid that occurs naturally in many foods and plant extracts and is also made industrially. It is used as a preservative in foods and drinks, where it is listed as E210, and in cosmetics and personal care products, where it also serves as a fragrance ingredient and pH adjuster. Its salts, such as sodium benzoate, are used the same way.
Key information
- Benzoic acid is a preservative and pH adjuster that occurs naturally in many foods and is listed as E210 in food.
- The CIR Expert Panel concluded in 2017 that it is safe in the present practices of use and concentration.
- EU scientific advisers found it safe at up to 0.5 percent in leave-on and 2.5 percent in rinse-off products.
- It can cause brief, non-allergic skin redness or swelling (contact urticaria) in some people.
More information
Commercial benzoic acid is made from chemical feedstocks such as toluene or phthalic anhydride. The Cosmetic Ingredient Review (CIR) Expert Panel assessed it together with its salts and benzyl alcohol and, in an amended report published in 2017, concluded that these ingredients are safe in the present practices of use and concentration. The industry survey the panel reviewed reported benzoic acid at up to 5 percent. In 2005 the European Commission’s Scientific Committee on Consumer Products (SCCP) concluded that benzoic acid and sodium benzoate are safe at up to 2.5 percent in rinse-off products, 1.7 percent in oral-care products and 0.5 percent in leave-on products.
Benzoic acid’s best-documented skin effect is non-allergic “contact urticaria,” brief redness or swelling where it touches the skin. In studies summarized by the SCCP it was common at higher test concentrations and appeared in some volunteers at 0.1 percent. An international assessment quoted by the SCCP described the effect as scarce in healthy people but more troublesome for people with frequent hives or asthma.
You may also read that benzoates form benzene. That concern comes from drinks: when benzoates and vitamin C are both present, heat and light can produce small amounts, and the FDA found the levels in beverages it tested were not a safety concern. The CIR panel judged that any benzene formed in cosmetics would be too little to be a relevant hazard.
Reality check: benzoic acid is a well-studied preservative with a long history of use in food. People prone to hives may want to watch for it, and for its salts, on labels.
Sources: International Journal of Toxicology (2017), via EPA HERO: Safety assessment of benzyl alcohol, benzoic acid and its salts, and benzyl benzoate; Cosmetic Ingredient Review: Benzyl alcohol, benzoic acid and its salts and ester, amended final report for panel review (2011); European Commission SCCP: Opinion on benzoic acid and sodium benzoate (2005); FDA: Questions and answers on the occurrence of benzene in soft drinks and other beverages
