Problem with Thick, White Cast Physical Sunscreen Cream

Hello,

Thank you for the information and photos you sent. I understand that thick, hard-to-spread cream that leaves a white cast is a common issue when making sunscreen, especially with physical filters.

The problems with thick texture, difficulty spreading, and white cast often arise from:

1. Type and Particle Size of Sunscreen Agents: Powder forms of sunscreen agents like Titanium Dioxide and Zinc Oxide (200nm) that you used tend to make the cream thicker and leave a white cast more easily than smaller particle sizes (Nano) or liquid dispersions that are already pre-dispersed.
2. Amount of Sunscreen Agents: Using a high amount of physical filters (e.g., 15% Titanium Dioxide + 15% Zinc Oxide = 30% total sunscreen in the body formula) to achieve a high SPF can also contribute to thick texture and white cast.
3. Other Ingredients in the Formula: The type and amount of emulsifiers, thickeners, or other ingredients also affect the texture and spreadability of the cream.

Recommendations for Improvement:

• Adjusting Finished Cream: Generally, it is not recommended to modify ingredients in a finished cream as it can lead to instability, separation, or loss of quality. Formula adjustments should be made before starting the next batch.
• Reducing White Cast and Improving Spreadability: As the staff previously recommended, Titanium Dioxide 15nm Liquid (ID 724) is a better option for beginners and helps significantly reduce white cast compared to the 200nm powder form. This is because it is a nano-sized particle in a liquid dispersion that is easier to incorporate.

Guidelines for Adjusting the Formula for the Next Batch:

1. Switch to Titanium Dioxide 15nm Liquid (ID 724): Try adjusting your formula by using Titanium Dioxide 15nm Liquid instead of Titanium Dioxide 200nm EasyDisperse (ID 236). This ingredient will help make the cream easier to spread and significantly reduce the white cast.
2. Consider the Amount of Sunscreen Agents: If a high SPF is desired, using only physical filters in high amounts can result in a heavy cream and prominent white cast. Combining Titanium Dioxide and Zinc Oxide in appropriate ratios, or potentially using certain chemical sunscreens (if desired), can help achieve the desired SPF with better texture and less white cast. However, for a purely physical filter formula, using Titanium Dioxide 15nm Liquid will be very helpful.
3. Adjust Other Ingredients: You might consider slightly adjusting the amount of Water-in-Oil EZ™ (ID 726) or Satin Cream Maker™ (ID 247), or adding emollients or silicone oils that improve spreadability, such as Cyclomethicone (ID 171), in an appropriate amount (but be careful not to destabilize the formula, especially when using Water-in-Oil EZ™ which requires a high water content).

Additional Recommendations:

• Study Example Formulations: It is highly recommended to review the example formulations provided for Titanium Dioxide 15nm Liquid (ID 724) in its product details. These often include basic formulas with suitable ratios of other ingredients, which will be very useful for getting started.
• Test in Small Batches: When adjusting the formula, always test by making small batches first to check the texture, stability, and white cast before making a larger quantity.

In summary, the issues you encountered are likely due to the type and amount of physical filter sunscreen agents used. Switching to Titanium Dioxide 15nm Liquid (ID 724) for your next batch will help address the problems of thick texture, difficulty spreading, and white cast. It is not recommended to adjust the finished cream.

Hope this advice is helpful.