Sunscreen Formulation Adjustment for Spreadability

The issue you are experiencing with your physical sunscreen formulation, where it is difficult to spread and leaves a white cast, is likely due to the relatively low proportion of the oil or silicone phase compared to the high concentration of physical sunscreen ingredients like Zinc Oxide. Physical sunscreen particles need to be well-dispersed in the oil or silicone phase to spread smoothly and evenly on the skin without dragging or leaving a white residue.

When you added Argan Oil, it helped improve spreadability because it increased the overall oil phase, allowing the Zinc Oxide to disperse better. However, since Argan Oil is a natural oil, it resulted in an oily and shiny finish, which is not your desired outcome.

To improve the spreadability and reduce the white cast without making the formula oily, you should increase the proportion of the oil/silicone phase using ingredients known for good spreadability and a non-greasy feel. Here are some recommended adjustments:

• Increase the Oil/Silicone Phase: Increase the total percentage of ingredients in the oil/silicone phase (LipidSoft™ F in your current formula). You might need to reduce the water phase percentage accordingly to keep the total at 100%.
• Choose Appropriate Emollients/Silicones: Consider replacing or supplementing LipidSoft™ F with emollients or silicones that offer excellent spreadability and a light, non-oily feel. Recommended options include:
  • LipidSoft™ Spread: This emollient is specifically designed for easy spreading and lightness.
  • Silicone Gel (e.g., Ultra Clear, Super Silky): Silicones provide a smooth, silky feel and improve spreadability significantly without adding oiliness.
  • Cyclomethicone: Another lightweight silicone that enhances spreadability and leaves a non-greasy finish.
• Adjust Polymethylsilsesquioxane Particle Size: The Polymethylsilsesquioxane 2microns in your formula helps with soft-focus and oil absorption, but a larger particle size can help reduce the white appearance. Consider using Polymethylsilsesquioxane 4.5microns instead. While this might slightly reduce skin coverage, it will improve transparency and reduce the white cast.

By increasing the non-polar phase with suitable emollients or silicones and potentially adjusting the particle size of powders like Polymethylsilsesquioxane, you can achieve a formula that spreads easily, minimizes white cast, and provides a more desirable non-oily finish.