Physical Sunscreen Formulation Challenges for High SPF/PA

Thank you for your question regarding a physical sunscreen formulation with SPF 40/PA+++ that is lightweight, non-greasy, blends naturally without a white cast, is moisturizing, long-lasting, and non-comedogenic.

Based on expert information and the properties of physical sunscreen filters, achieving a purely physical sunscreen with SPF 40/PA+++ that also meets all your desired aesthetic properties (especially no white cast on fair-yellow skin) is highly challenging.

Physical sunscreens primarily use Titanium Dioxide and Zinc Oxide. To reach a high SPF and PA level like 40/PA+++, a significant concentration of these filters is required. The inherent white color of these oxides, particularly Titanium Dioxide, often leads to a visible white cast when used at high levels. While using nano-sized particles or specially treated dispersions can significantly reduce the white cast and improve texture, completely eliminating it while maintaining high protection can be difficult.

For instance, products like Titanium Dioxide Transparent (15nm, Water-Dispersion) and Titanium Dioxide Transparent (10nm, C12-15 Alkyl Benzoate Base) are designed with very small particle sizes (10-15nm) and special coatings to minimize whiteness and allow for dispersion in water or oil bases, respectively. Similarly, Zinc Oxide Transparent Dispersion (C12-15 alkyl benzoate Base) and Zinc Oxide 40nm Dispersion (Water Base) offer nano-sized zinc oxide in different dispersion bases that aim to be transparent on the skin.

However, even with these advanced forms, formulating a pure physical sunscreen to SPF 40/PA+++ without any white cast, while also ensuring a lightweight, non-greasy, and long-lasting feel, is complex. As previously mentioned by the staff, achieving this level of performance often necessitates the use of hybrid formulations that combine physical and chemical filters, or relies on specific, often proprietary, dispersion technologies.

Therefore, providing a complete, guaranteed formula for a pure physical SPF 40/PA+++ sunscreen that is truly non-whitening and meets all your requirements is not feasible with the inherent limitations of physical filters at high concentrations. The products mentioned above represent the types of ingredients used to minimize white cast in physical sunscreens, but a successful high-SPF, non-whitening pure physical formula is technically very difficult to achieve.