Potassium Benzoate

Potassium benzoate is the potassium salt of benzoic acid, a naturally occurring compound found in foods like berries and dairy products. In skincare, it functions as a preservative—an ingredient added to prevent the growth of bacteria, fungi, and other microorganisms that could compromise product safety and stability.It works by inhibiting microbial proliferation, which helps extend shelf life and maintain product integrity from manufacture through to use. Potassium benzoate is relatively uncommon in skincare formulations, appearing in approximately 0.2% of products.

Potassium benzoate prevents microbial growth by disrupting the cell membranes of bacteria and fungi, inhibiting their ability to multiply. This mechanism makes it effective at low concentrations, which is why preservatives are typically used at levels well below 1%.The preservative function is particularly important in water-based or emulsified products, where moisture creates an environment where microorganisms could otherwise thrive. By maintaining microbial control, potassium benzoate protects both product integrity and skin safety.

You don't need to do anything differently when using a product containing potassium benzoate. Simply follow the manufacturer's instructions for application and storage. To maximise product longevity, store formulations away from direct sunlight and heat, and keep container lids sealed between uses.

Potassium benzoate is generally well-tolerated and approved for cosmetic use by major regulatory bodies. Allergic contact dermatitis is rare but possible; discontinue use if you experience unexpected irritation.