Before we begin:
First of all, whenever we talk about ingredients, we should clarify a few things:
- All ingredients authorized by the EU (1223/2009) are considered "safe" (except for neurotoxicity and ecotoxicity) within the maximum allowed concentration.
- Ingredient "risks" are just that, "risks"; for example, an ingredient with CMR activity (carcinogenic, mutagenic, reprotoxic) will not necessarily cause cancer in consumers.
Our goal is to list the different risks for children to raise your awareness.
What is Sodium Benzoate?
In reality, sodium benzoate is the salt of benzoic acid. Benzoic acid is the active form that prevents bacterial growth, but it dissolves poorly in water, which is why the industry uses it in salt form for easier integration.
In the presence of water at an acidic pH, sodium benzoate will (partially) transform into benzoic acid.
It is naturally found in cheeses and some fruits and its dosage is regulated:
In cosmetics:
The maximum authorized concentration in finished preparations is:
- 2.5% for rinse-off products, with the exception of oral hygiene products
- 1.7% for oral hygiene products
- 0.5% for leave-on products
In food:
In the United States, the dose cannot exceed 0.1%.
But in Europe, this limit is stricter and determined by the type of food: 0.015% in beverages and 0.5% for liquid egg products.
However, it is an extremely popular preservative found in medicines, food supplements, food...
But also now in many cosmetics with the trend of organic cosmetics.
And even if each individually respects the authorized doses, by accumulating several types of products, the cocktail effect is very concerning for us, and we'll explain why.
Why avoid benzoic acid?
Benzoic acid has neurotoxic activity
According to a study conducted on mice, scientists have established a neurotoxic effect of sodium benzoate:
For 4 weeks, subjects who ingested between 130 to 225 mg/kg per day showed aggressive behavior, a much lower level of learning and coordination, which suggests obvious oxidative stress in the brain. (1)
In just 4 weeks, that makes our hair stand on end, doesn't it?
In 2007, the link between hyperactivity in children under 9 and sodium benzoate consumption was published in "The Lancet" by Dr. McCann. (2)
Benzoic acid penetrates the skin barrier
At this point, you might think: food is one thing, we ingest it and it enters our body, but what about in moisturizer?
Indeed, we don't eat our cosmetics (normally), so one might believe that the presence of benzoic acid (sodium benzoate) in skincare products is "less serious."
However, benzoic acid is a set of small lipid-soluble molecules (which dissolve poorly in water), and what concerns us about this type of chemical structure is that it rapidly penetrates the skin...
Its absorption is 6.54 to 11.87 mg/cm2 per hour. That's 70.7% absorption into the blood (according to 8 laboratories).
So, there's no need to eat your shower gel for it to be dangerous...
Reaction with other ingredients
Benzoic acid can be reduced (transformed) by certain reducing acids, such as ascorbic acid (vitamin C), into benzene (a carcinogenic molecule).
This is why the fruit juice industry often excludes sodium benzoate from its products.
However, in cosmetics, we have already seen sodium benzoate combined with very fresh fruit extracts or vitamin C derivatives, which we find more than concerning for consumers...
The more it's used, the less effective it is...
Perhaps you are aware of the problem of antibiotic-resistant bacteria? By using them too much, bacteria have developed resistance to certain antibiotics.
Well, it's the same for preservatives! (3)
If we overuse and abuse the same family of preservatives, microorganisms will eventually develop resistance...
Due to its very low cost, the cosmetic industry has overused sodium benzoate, and the organic cosmetics industry continues to add this preservative to their formulas up to the authorized limit.
And more bad news for consumers...
Even if it is well-rated in Yuka and other scanning apps, even if it is massively used in organic cosmetics, we exclude it from all our products.
If you have more questions about this (or any other) preservative, do not hesitate to write to us: coucou@lilikiwi.fr, we will be happy to answer you!
Take good care of yourselves and check your labels.
Sources:
(1) Javad Khoshnoud et al. *JBiochemMolToxicol.*2017;22022. ****(2) https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(07)61306-3/abstract(3)https://www.sciencedirect.com/science/article/pii/S0022030297761800