Sodium benzoate, or Benzoate de Sodium, is derived from benzoic acid, which is naturally present in milk fermentation or in fruits (such as blueberries and cranberries). It is used as a preservative. The law requires the protection of skincare products from any external microbial contamination, hence the importance of adding preservatives. The question that arises is: what is the utility of sodium benzoate? Let's focus.
What is "Sodium Benzoate" and what is its purpose?
Summary
Published on February 1, 2024, by Stéphanie, PhD, Doctorate in Life and Health Sciences — 3 min of reading
Everything you need to know about Sodium Benzoate
In addition to being present in certified organic skincare products, sodium benzoate is also used in food products, where it is known as E211. It prevents the formation of bacteria and fungi in water-based skincare products.
Marketed in the form of granules or crystalline powder, sodium benzoate is represented by the chemical formula NaC7H5O2. It is a weak base with a solubility of 630g/L at 20°C. It is the result of an acid-base reaction between benzoic acid and soda (NaOH).
Sodium benzoate is naturally found in certain fruits: prunes, cranberries, bilberries, cinnamon, and cloves. In addition to being a food preservative, it is also present in shampoos and shower gels.
Once solubilised in a liquid care product, sodium benzoate transforms into benzoic acid. This active ingredient is present in numerous varieties of plants. Acting on yeasts and bacteria, sodium benzoate complements potassium sorbate, which targets bacteria.
Sodium Benzoate: what is its purpose?
Sodium benzoate inhibits the growth of microorganisms in skincare products. It can be used on its own. However, it can also be combined with other preservatives such as grapefruit seed extract or potassium sorbate.
Similar to potassium sorbate and benzyl salicylate, sodium benzoate is among the preservatives (known as clever preservatives) authorised by European organic labels. The presence of water encourages the growth of yeasts, bacteria, moulds, and fungi. Skincare products composed of water (gels, creams or lotions) or with a watery texture are no exception to this rule. To avoid any contamination, the addition of a preservative is necessary. Moreover, this helps to extend the shelf life of the skincare product. The function of preservatives is:
To eliminate bacteria;
To prevent the emergence of yeasts;
To avoid less mould.
It is present in:
Shower gels;
Baby wipes and cleansing waters;
Shampoos for coloured or highlighted hair.
Sodium Benzoate: What's the Risk?
Sodium benzoate is not suitable for sensitive skin, as it can trigger skin reactions or allergic reactions (allergic rhinitis or asthma attacks). It is contraindicated in children, as it can promote the onset of hyperactivity symptoms. Sodium benzoate present in shower gels can cause allergies in the form of itching and eczema.
Before using this active ingredient, it is advisable to test it in the crook of your arm and wait approximately 48 hours. If irritation occurs, cease using the skincare product.
The recommended dosage of sodium benzoate in creams, lotions, and foaming treatments is between 0.1% and 1%.
