Science
Mechanism of Action
This ingredient functions as an antimicrobial by inhibiting the proliferation of bacteria, molds, and other microorganisms in water-based products. It is the inactive salt of benzoic acid, which converts to its active form, benzoic acid, in acidic environments (pH below 4.0). In this active state, it predominantly acts as an anti-fungal agent with some antibacterial properties.
Research
Clinical Evidence
High confidence0.5%
Key findings
- 01 Clinical assessments indicate that sodium benzoate is generally non-irritating to most skin types, including sensitive skin, when incorporated as a preservative at concentrations between 0.5% and 1.0%.
Transparency
Dusting Analysis
Sodium benzoate is a functional preservative, used at concentrations necessary to ensure microbial stability and product safety, adhering to regulatory limits. Its inclusion is for essential product integrity rather than being used at cosmetically insignificant or excessively high, non-functional levels.
The Formula
Formulation
Stability
Optimal antimicrobial efficacy is achieved in acidic conditions, specifically within a pH range of 2.5 to 4.0, where it converts into its active benzoic acid form. It also contributes to the pH stabilization of cosmetic formulations.
Conflicts
- Vitamin C (ascorbic acid), particularly in the presence of heat and light, due to the potential for benzene formation.
- Strong acids, which can lead to its premature decomposition into benzoic acid.
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) has determined Sodium Benzoate to be safe for use in cosmetics, subject to specific concentration and use limitations. European Union legislation permits its use up to 0.5% in leave-on products, 2.5% in rinse-off products, and 1.7% in oral care products. While generally recognized as safe (GRAS) for food by the FDA, a theoretical concern exists regarding benzene formation when combined with Vitamin C under specific conditions; however, the FDA indicates low levels in beverages do not pose a health risk.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Sodium Benzoate is an essential, highly effective, and generally well-tolerated preservative critical for maintaining the microbial stability and safety of water-based skincare formulations.
Related
Similar Ingredients
Finding similar ingredients…