Ethylparaben is a paraben-family cosmetic ingredient primarily used for its antimicrobial preservative function in cosmetic and personal care formulations. It is chemically known as Ethyl 4-Hydroxybenzoate and has the molecular formula C₉H₁₀O₃ with a molecular weight of 166.17 g/mol. Its CAS Number is 120-47-8 and its EC Number is 204-399-4.
Ethylparaben is described as a crystalline material, typically appearing as small colourless crystals or a white crystalline powder. The International Pharmacopoeia classifies Ethyl hydroxybenzoate as an antimicrobial preservative.
Ethylparaben is the ethyl ester of 4-hydroxybenzoic acid. It belongs to the hydroxybenzoate ester family commonly known as parabens.
Its chemical properties make it useful as a preservative ingredient in formulations where control of microbial growth is required. Ethylparaben is also commonly considered alongside other hydroxybenzoates as part of a broader preservation system.
Common names include:
Ethylparaben functions primarily as an antimicrobial preservative ingredient. Preservation is particularly relevant to cosmetic products containing water or other formulation components that can support microbial growth.
The effectiveness of a preservative system depends on the finished formulation rather than the raw material alone. Factors such as concentration, formulation pH, water phase, packaging, manufacturing conditions and combinations with other preservatives can affect overall preservation performance.
The International Pharmacopoeia notes that Ethyl hydroxybenzoate is normally used in combination with other hydroxybenzoates.
Ethylparaben may be considered in a variety of cosmetic and personal care formulations, including:
The actual suitability and permitted concentration should always be established for the finished formulation and its target market.
Ethylparaben should be evaluated as part of the complete preservation system. Formulators should assess compatibility with other preservatives, surfactants, emulsifiers, fragrances and other functional ingredients.
Ethylparaben has very low solubility in water. The International Pharmacopoeia describes it as very slightly soluble in water, sparingly soluble in boiling water and freely soluble in ethanol.
This characteristic is important when determining the appropriate manufacturing process and incorporation method.
Preservative performance can be influenced by formulation pH. The finished cosmetic formulation should therefore be evaluated at its intended pH and under realistic storage conditions.
The processing method should provide adequate distribution of Ethylparaben throughout the formulation. Where a solvent or co-solvent is required, its compatibility with the complete formulation should be evaluated.
Compatibility should be assessed with:
Ethylparaben has:
These characteristics are documented by PubChem and the International Pharmacopoeia.
For commercial cosmetic ingredient supply, Ethylparaben should be controlled against a documented specification corresponding to the actual supplied grade.
The 2025 International Pharmacopoeia specifies that Ethyl hydroxybenzoate contains not less than 99.0% and not more than 101.0% of C₉H₁₀O₃, calculated with reference to the dried substance.
Quality evaluation may include:
For the SDP product page, the numerical limits should be taken from the actual approved SDP specification or COA. Generic values should not be presented as SDP specifications.
Ethylparaben is covered together with Methylparaben in the EU Cosmetics Regulation's preservative provisions for 4-hydroxybenzoic acid and its methyl- and ethyl-esters and their salts.
The European Commission's SCCS documentation discusses the regulatory limit of 0.4% expressed as acid for the relevant entry and explains the molecular-weight conversion for ester forms.
This should not be interpreted as a universal permitted-use level in every country. Cosmetic manufacturers should verify the current requirements of the specific target market, product category and applicable legislation before determining the finished-product concentration.
Ethylparaben should be kept in a well-closed container and protected from contamination and unsuitable environmental conditions. The International Pharmacopoeia specifically recommends storage in a well-closed container.
Recommended handling considerations include protection from:
Actual storage requirements should follow the commercial product's specification and Safety Data Sheet.
Ethylparaben is an established cosmetic preservative ingredient from the paraben family. With CAS Number 120-47-8, molecular formula C₉H₁₀O₃ and molecular weight 166.17 g/mol, it is relevant to the development of various cosmetic and personal care preservation systems.
Its low water solubility, crystalline physical form and antimicrobial preservative function are important considerations during formulation development. Finished products should be evaluated for preservation performance, compatibility, concentration and applicable regulatory requirements.
| Parameter | Specification |
|---|---|
| Appearance | White or colourless crystals / white powder |