Physical Sunscreen Formulation with Titanium Dioxide and Zinc Oxide

You asked about the percentages of Titanium Dioxide 200nm EasyDisperse and Zinc Oxide 200nm EasyDisperse needed to achieve SPF 20 and SPF 30 in a physical sunscreen.

Based on the product information:

• Titanium Dioxide 200nm EasyDisperse: The description for this product indicates it is primarily for use in makeup products and directs users to select other types of Titanium Dioxide specifically intended for UV protection in sunscreen formulations. Therefore, this particular grade of Titanium Dioxide is not recommended for your physical sunscreen application.

• Zinc Oxide 200nm EasyDisperse: This product is suitable for use as a physical sunscreen ingredient. However, the product description does not provide a specific chart or formula to determine the exact percentage needed to reach a target SPF (like 20 or 30) when used alone or in combination. Achieving a specific SPF value requires careful formulation and often necessitates in-vitro or in-vivo SPF testing of the final product.

Determining the precise percentage of UV filters like Zinc Oxide needed for a specific SPF is complex and depends on various factors, including the particle size and dispersion of the active ingredient, the other components in the formula, and the required broad-spectrum protection (UVA/UVB balance). General guidelines exist, but accurate SPF claims require testing.

Therefore, based on the available product descriptions, I cannot provide the exact percentages of Zinc Oxide 200nm EasyDisperse required for SPF 20 or SPF 30.