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Sodium Benzoate

Well toleratedPreservativepreservative

No meaningful concern for most people; irritation is possible but rare.

Also written as: Benzoic Acid, Sodium Salt · E211

What it is

Sodium benzoate is the sodium salt of benzoic acid, which occurs naturally in cranberries, prunes and cinnamon. In water it sits in equilibrium with free benzoic acid, and only the free acid is antimicrobial, which is why it is used almost exclusively in products with a pH below about 5. It is common in 'clean beauty' and natural-positioned masks because it is also a permitted food preservative.

What it does well

  • Well tolerated on skin, with a long food-safety record

    The Cosmetic Ingredient Review panel assessed benzyl alcohol, benzoic acid and sodium benzoate together and found them safe for use in cosmetics at the concentrations then in use. Allergic contact dermatitis to it is rare.

    Strong evidence

  • Works well alongside potassium sorbate in low-pH masks

    Sodium benzoate is stronger against yeast and bacteria while sorbate is stronger against moulds, so the two are routinely combined in acidic gel and essence formulas.

    Moderate evidence

Worth knowing

  • Can cause transient stinging, redness or hives on contact

    Benzoates are classic causes of non-immunological contact urticaria: a short-lived flush or wheal, most often around the mouth, that is not a true allergy. It fades within an hour and does not indicate lasting harm.

    Matters most toPeople with reactive or easily flushed skin, especially around the lips.

  • Only preserves acidic products

    Above roughly pH 5 it loses most of its activity, so a formula relying on it alone must stay acidic. This is a formulation limitation rather than a safety issue.

    Matters most toNobody in particular; it matters to formulators, not users.

Where the EU stands

Approved preservative (Annex V)

Permitted preservative, expressed as benzoic acid: max 0.5% in leave-on products, 1.7% in oral products and 2.5% in rinse-off products.

Regulation (EC) No 1223/2009, Annex V entry 1 · source ↗

Sources (2)

Every link goes to the original: a journal, a PubMed record or an EU document.

  1. [1]
    Final report on the safety assessment of Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate

    International Journal of Toxicology (Cosmetic Ingredient Review) · 2001

    The expert panel concluded these three related preservatives are safe for use in cosmetic products at the concentrations described in the review.

  2. [2]
    Perioral contact urticaria from sodium benzoate in a toothpaste

    Contact Dermatitis · 1996

    A documented case of immediate, non-allergic contact urticaria around the mouth triggered by sodium benzoate in a personal-care product.

Masks that contain Sodium Benzoate