Sodium Benzoate( Cosmetic Preservative )-CAS 55406-53-6

Sodium Benzoate( Cosmetic Preservative )-CAS 55406-53-6

Sodium Benzoate is a widely used, cost-effective cosmetic preservative and the sodium salt of benzoic acid, a compound naturally found in many fruits and plants including cranberries, prunes, and cinnamon. With the INCI name SODIUM BENZOATE and CAS number 532-32-1, this versatile ingredient has been used safely in food, cosmetics, and pharmaceuticals for decades. It functions by penetrating microbial cell membranes and disrupting intracellular pH balance, effectively inhibiting the growth of yeast, mold, and certain bacteria. Sodium Benzoate is most effective in acidic conditions (pH 2.5–4.0), making it an ideal preservative choice for acidic formulations such as AHA/BHA products, vitamin C serums, and acidic toners. Its excellent water solubility, thermal stability, and broad global regulatory acceptance make it one of the most popular preservatives in the cosmetic industry. As a naturally-derived option (benzoic acid occurs naturally in plants), it also appeals to consumers seeking more natural preservation alternatives to synthetic parabens and formaldehyde donors.

Key Benefits

• Broad-spectrum antimicrobial: Effective against yeast, mold, and various bacteria

• Excellent for acidic formulas: Peak efficacy at pH 2.5–4.0, ideal for AHA/BHA and vitamin C products

• High water solubility: Dissolves easily in water, simple to incorporate into formulations

• Cost-effective: Economical price point with proven efficacy, widely available

• Globally approved: Meets China, EU, US FDA and major global regulatory standards

• Naturally derived: Benzoic acid occurs naturally in many fruits and plants

• Thermally stable: Withstands high manufacturing temperatures, no degradation

• Colorless and odorless: Does not affect product appearance, color, or fragrance

• Low irritation: Very mild at recommended use levels, good skin compatibility

• Synergistic effects: Works well with other preservatives like potassium sorbate for enhanced protection

Applications

• Acidic toners and essences: Recommended usage 0.1%–0.5%, ideal for pH 3–4 formulas

• AHA/BHA exfoliating products: Recommended usage 0.1%–0.5%, optimal for acidic exfoliants

• Vitamin C serums and brightening products: Recommended usage 0.1%–0.3%

• Shampoos and hair cleansers: Recommended usage 0.1%–0.5%, rinse-off category

• Body washes and shower gels: Recommended usage 0.1%–0.5%, rinse-off category

• Facial cleansers and face washes: Recommended usage 0.1%–0.5%, rinse-off category

• Face creams and lotions: Recommended usage 0.1%–0.5%, leave-on category

• Toothpaste and oral care products: Recommended usage 0.1%–1.7%, per regulatory limits

• Hair conditioners and hair masks: Recommended usage 0.1%–0.3%

• Facial masks and sheet masks: Recommended usage 0.1%–0.3%

Certificate Of Analysis (COA)

Frequently Asked Questions (FAQ) 

Q1: What are the regulatory limits for Sodium Benzoate in cosmetics in China and the EU?

A: In China, as a preservative the limit is max 0.5% (as benzoic acid). As a non-preservative restricted ingredient, it can be used up to 2.5% in rinse-off products and 1.7% in oral care (as acid). In the EU, the limits are similar: 0.5% as preservative, with higher limits for other functions. Always verify specific product type restrictions and label requirements for your target market.

Q2: Why does Sodium Benzoate work best in acidic conditions? Does it work in neutral formulas?

A: Sodium Benzoate dissociates into benzoate ions in water. The undissociated benzoic acid form is the active antimicrobial form that can penetrate microbial cell walls. At lower pH (more acidic), more of the benzoate converts to the active undissociated form. It still works at neutral pH but with reduced efficacy. For best results, use in formulas below pH 5.0, ideally pH 2.5–4.0. In neutral or alkaline formulas, consider combining with other preservatives.

Q3: Is it true that Sodium Benzoate reacts with vitamin C to form benzene? Is it safe?

A: Under certain conditions (high temperature, UV exposure, low pH, high concentrations), Sodium Benzoate can react with ascorbic acid (vitamin C) to form trace amounts of benzene. However, at typical cosmetic use levels (both ingredients below 1%), the reaction produces negligible amounts well below safety limits. Regulatory bodies worldwide have confirmed that cosmetic products containing both ingredients at normal use levels are safe. To minimize risk, avoid high concentrations of both together and store products away from heat and light.

Q4: How does Sodium Benzoate compare to potassium sorbate and parabens?

A: Sodium Benzoate is most effective against yeast and mold in acidic conditions, while potassium sorbate has a similar spectrum but works slightly better at higher pH. Both are often used together for synergistic effect. Compared to parabens, Sodium Benzoate is less effective against bacteria and requires acidic conditions, but is considered a more "natural" alternative since benzoic acid occurs naturally in plants. It is also cheaper and more widely available. For full broad-spectrum protection, it is usually combined with other preservatives.

Q5: What compliance documents and certifications are available?

A: Batch COA, SDS/GHS safety data sheet, Certificate of Origin, China Cosmetic Ingredient Inventory confirmation (No. 01289), technical data sheet, heavy metal and microbiological test reports, purity assay report, and food grade E211 certification. HALAL and KOSHER certifications are available from most suppliers. The ingredient is listed in both EU Annex V and China's approved preservative list, supporting global market access.

Q6: What is the shelf life and are there any storage or stability concerns?

A: Shelf life is 24 months in original sealed packaging. Store in a cool, dry, well-ventilated area away from direct sunlight and moisture. Sodium Benzoate is very stable across a wide temperature range and can withstand typical cosmetic manufacturing temperatures. It is hygroscopic so keep containers tightly sealed. It is compatible with most cosmetic ingredients but avoid high concentrations of strong oxidizing agents. Always conduct stability and challenge testing in your specific formulation.

Contact Us

 💌 Contact us today for technical data, formulation guidance, and competitive pricing! E-mail: 

sales10@huilinbio-tech.com