Formulating Physical Sunscreen SPF 40+ PA+++ (Lightweight, Non-Whitening)

Based on your goal to create a 100% physical sunscreen that is lightweight and non-whitening using Titanium Dioxide 15nm Liquid (15%) and Zinc Oxide 200nm EasyDisperse™ (10%), here is the information:

• Feasibility of SPF 40+ PA+++: Based on the concentrations you plan to use, achieving SPF 40+ PA+++ is possible. However, as the staff mentioned, the final SPF and PA values can only be confirmed through laboratory testing of the finished product.
• Importance of the Full Formulation: The effectiveness (SPF/PA) and the texture (lightweight, non-whitening) of your sunscreen depend significantly on the entire formulation, not just the percentage of UV filters. Factors like how well the filters are dispersed, the type of emulsifier used, and the presence of other ingredients play a crucial role.
• Formulation Tips:
  • Using nano-sized or dispersed forms of Titanium Dioxide and Zinc Oxide (like the ones you chose) helps minimize the whitening effect and can contribute to a lighter texture.
  • Proper dispersion of the UV filters in the oil phase or a suitable vehicle is critical for achieving maximum protection and a smooth texture.
  • Other ingredients, such as certain waxes (like Polyethylene Wax mentioned by the staff) or film-formers, can help boost SPF/PA and improve water resistance and texture.
  • Choosing appropriate emulsifiers and rheology modifiers is essential for creating a stable, lightweight, and non-greasy emulsion.
• Example Formulations: The staff recommended checking the product details page for "Titanium Dioxide 15nm Liquid" (Product ID 724) for example formulations. This page may provide starting points or ideas for your formulation.

In summary, your chosen ingredients and concentrations are a good basis for a high-SPF physical sunscreen. Success in achieving the desired SPF/PA and texture will depend heavily on the careful design of the complete formulation.