Silicone-Based Sunscreen Formulation

You are looking to create a silicone-based sunscreen and have questions about specific ingredients and the silicone base.

Regarding the ingredients you mentioned:

• Titanium Dioxide 200nm EasyDisperse™ (ID 236): The description for this product states it is for make-up products only and not for use in sunscreen for UV protection. You should select a Titanium Dioxide specifically intended for sunscreen applications if you wish to include it for UV filtering.

• Zinc Oxide 200nm EasyDisperse™ (ID 248): Using 25% of this product will provide significant UV protection. The description mentions it gives "low whiteness" compared to larger particle sizes, and the small particle size helps reduce shine. However, as a physical sunscreen ingredient, it may still leave some degree of whiteness or shine, although this version is designed to minimize it.

• MatteSilica 5™ (ID 518): Using 15% MatteSilica 5™ is within the recommended usage rate (0.1-20%) and is suitable for absorbing excess oil and providing a matte finish, which aligns with your goal for oily skin.

For the silicone base, you have a few options depending on the desired feel and finish:

• Cyclopentasiloxane (Low-Odor Cyclomethicone) (ID 171): This is a lightweight, volatile silicone that evaporates quickly, leaving a smooth, non-sticky feel. It is a common base for dispersing powders like Zinc Oxide in silicone-based formulas.

• Silicone Gel (High Matte, Dimethicone Base) (ID 34349): This silicone gel provides a matte finish and a thicker texture. It can help improve the feel of the product, making it soft, smooth, and light. This could be a good option if you want to emphasize the matte aspect of the sunscreen.

You can use either Cyclopentasiloxane or Silicone Gel (High Matte, Dimethicone Base), or a combination, as the base for your silicone sunscreen formulation, incorporating the Zinc Oxide and MatteSilica into the silicone phase.

Remember to ensure proper dispersion of the Zinc Oxide in the silicone base for effective UV protection and formula stability. The description for Zinc Oxide 200nm EasyDisperse™ suggests mixing it in Cyclomethicone silicone in a 1:1 ratio initially before incorporating into the main formula.