Classification of Sodium Metabisulfite in Serum Formulation for Registration

Sodium metabisulfite is commonly used in cosmetics as both an antioxidant and a preservative.

• As an antioxidant/reducing agent: While sodium metabisulfite does have antioxidant properties, its primary role in many cosmetic formulations, especially at lower concentrations like 0.0105%, is often to protect other ingredients from oxidation rather than acting as a primary reducing agent for skin benefits. If it was not approved under 'antioxidant' or 'reducing', it could be due to several reasons:

  • Specific regulatory definitions: Regulatory bodies might have strict definitions for what qualifies as an "antioxidant" or "reducing agent" in terms of its primary function and efficacy claims for the final product.
  • Concentration: The concentration of 0.0105% might be considered too low to effectively claim a primary antioxidant or reducing function for the finished product, or it might be below a threshold for certain classifications.
  • Other ingredients: The presence of other ingredients in the formulation might influence how sodium metabisulfite's function is perceived or classified.

• As a preservative: Sodium metabisulfite is widely recognized and approved as a preservative in cosmetic products due to its ability to inhibit microbial growth. Given its common use and function, it is highly likely to be approved when declared as a 'Preservative', especially at the concentration of 0.0105%, which is within typical usage levels for this purpose.

It's important to consult the specific cosmetic regulations of the country where you are registering the product, as classifications and allowable concentrations can vary.