Sodium Benzoate Cosmetic Preservative
CAS Number: 532-32-1
Sodium Benzoate is a water-soluble preservative effective at pH below 5.5 (pKa 4.2), where the active undissociated benzoic acid form predominates. It is widely used in acidic toners, AHA serums, and micellar water, and is frequently combined with potassium sorbate for broad-spectrum coverage against bacteria, yeasts, and molds. Approved under COSMOS and ECOCERT natural cosmetic standards.
Technical Specifications
| purity | ≥99.0% (anhydrous basis) |
| appearance | White granular powder |
| pH 10pct solution | 8.0–9.5 |
| effective pH range | ≤5.5 |
Applications
- Acidic facial toners and essences (pH 3.5–5.5)
- AHA/BHA exfoliant serums
- Micellar cleansing water
- Natural and organic certified cosmetics
- Fruit-based skin care formulations
Key Features
- Sodium Benzoate provides effective preservation in acidic leave-on and rinse-off cosmetics
- COSMOS and ECOCERT approved for natural formulation programs
- Synergistic with potassium sorbate for complete broad-spectrum protection
- Highly water-soluble, easy to incorporate into aqueous phases