Sodium Benzoate: An In-Depth Look
As you may know or may have read in our harmful chemicals blog, cosmetics need preservatives to prevent the growth of bacteria. One of the preservatives we use in place of the toxic alternatives is sodium benzoate. There is mis-information about this benign ingredient posted around the web, claiming it is unsafe and toxic to humans. The bottom line is that preservatives are needed to keep personal care products safe, and not all preservatives are harmful to your health.
Sodium benzoate is the salt of benzoic acid. It is made by neutralizing benzoic acid, and ingredient that is present in numerous products ranging from food to cosmetics. It is also naturally occurring in teas and some fruits and vegetables, so try as you might, it’s in foods too – and “healthy ones” at that. In the EU, after numerous studies, the final opinion is that benzoic acid and sodium benzoate are safe for use for preservative and non-preservative purposes in cosmetic rinse-off products at a maximum concentration of 2.5 % and in cosmetic oral-care products at a maximum concentration of 1.7 %, and in leave-on products up to 0.5%. 2 The concentration of sodium benzoate used by Kavella never exceeds 0.25% in any product.
Some of the strictest certification organizations for natural products in the world accept sodium benzoate as a preservative because it is a safe and effective way to protect consumers from bacteria and mold developing in the bottle. The Natural Products Association, Cosmos and even ECOCERT all allow sodium benzoate in their certified natural products.
So, with the studies to back up the legal authorities on the matter, why is there still concern and mis-information? It seems the mis-information on sodium benzoate most likely arose out of the concern of presence of benzene in beverages, which stemmed from articles like this one published in 2008, “Occurrence of benzene as a heat-induced contaminant of carrot juice for babies in a general survey of beverages”.3 The study actually analyzed a long list of beverages for benzene contamination, but found that the only detectable levels were in carrot juice intended for infants, which of course would raise concern from studies on benzene.Benzene is a chemical that has been linked to increased risk of leukemia and other blood cancers.4 While sodium benzoate doesn’t contain benzene, it can form benzene when combined with Vitamin C, also known as ascorbic acid.4
There is a misconception that oils can contain ascorbic and therefore something like sweet orange essential oil should not be combined with sodium benzoate. This is, in fact, not the case. Ascorbic acid is a water-soluble vitamin and would not be found in oils.
As a consumer, you can reduce the risk of benzene exposure, by not buying products, especially soft drinks that list both ascorbic acid and sodium benzoate as ingredients. As a food-grade preservative, most of the concerns regarding sodium benzoate result from studies that have been done on ingesting it, especially at high amounts. Because of this, information gets incorrectly cited and rewritten when discussed as a cosmetic preservative. Some blogs even completely reworded or misquote studies, changing what was said in the article to put a negative spin on it, despite the rest of the article saying that it was a generally safe ingredient (except when combined with ascorbic acid, as we know.)
Don’t believe everything you read online, especially if it is unsourced.
For example, some blogs claim that sodium benzoate can cause disorders such as Alzheimer’s and Parkinson’s disease. After researching this claim, we found that the actual quote from the study is quite the opposite. It states, “The clinical administration of sodium benzoate is of proven benefit for many patients with urea cycle disorders, while recent studies indicate it may also be advantageous in the treatment of multiple sclerosis, schizophrenia, early-stage Alzheimer’s disease and Parkinson’s disease.” If you are interested, see source 5 below on a study they did, using sodium benzoate as a treatment for schizophrenia. Spoiler alert, the results showed improvement in cognitive functioning of the patients.
Another claim made by blogs is that sodium benzoate attacks our mitochondria, which is also a false claim based on misquoted (and always unsourced) studies. Sodium benzoate is metabolized in the mitochondria, but it does not attack it. The actual mechanism is as follows: “Sodium benzoate is a widely used preservative found in many foods and soft drinks. It is metabolized within mitochondria to produce hippurate, which is then cleared by the kidneys.” 6 and again here: “Benzoic acid is conjugated in the liver with glycine to form hippuric acid, the major metabolite. In healthy adults, up to 97% of the dose of sodium benzoate is excreted as hippuric acid in the urine within 4 hours.” 7
We hope this information, as well as providing both cited studies and direct quotes, will help ease any concerns regarding this ingredient. Some of the strictest certification organizations for natural products in the world accept sodium benzoate as a preservative because it is a safe and effective way to protect consumers from bacteria and mold developing in the bottle. The Natural Products Association, Cosmos and even ECOCERT all allow sodium benzoate in their certified natural products.
When we research ingredients, we look only at facts that are well documented and cited. There is a lot of incorrect information on the internet, and we aim to cut right through the noise. We are highly dedicated to the safety of stylists and clients and to maintain transparency in an industry that often does not.
If you’d like to learn more about this topic, check out this article by chemist Derek Lowe: https://blogs.sciencemag.org/pipeline/archives/2017/07/24/sodium-benzoate-nonsense