Dispersing Micronized Zinc Oxide in Water Gel for Sunscreen

Question

I am formulating a sunscreen using uncoated Micronized Zinc Oxide in a water gel base (like water + Pro Polymer). Is it possible to disperse uncoated Micronized Zinc Oxide in this type of water gel? What mixing method is required to achieve sufficient and even dispersion for effective sun protection? Is a regular blender sufficient for this purpose, or is a high-speed homogenizer necessary? What are alternative physical sunscreens that disperse more easily in water gel bases without needing a homogenizer?

MySkinRecipes Expert · Accepted Answer

Regarding the dispersion of uncoated Micronized Zinc Oxide in a water gel (like water + Pro Polymer):

Is it possible? Yes, it is possible to disperse uncoated Micronized Zinc Oxide in a water gel.
Required Mixing Method: To achieve sufficient and even dispersion for effective sun protection, high-speed blending using a homogenizer (10,000 RPM or higher) is necessary.
Regular Blender: A regular blender is not sufficient. It will not disperse the Zinc Oxide adequately, leading to clumping. This results in uneven sun protection, which can be detrimental and potentially cause uneven skin tone.

For water-based gel formulations, the staff recommends using alternative sunscreen types that disperse more easily without a homogenizer, such as:

Organic/Chemical sunscreens.
Physical sunscreens that are pre-dispersed liquids (like Zinc Oxide NanoLiquid™ or Titanium Dioxide NanoLiquid™).
If the gel is thick enough, EasyDisperse™ physical sunscreens (like Zinc Oxide 200nm EasyDisperse™ or Titanium Dioxide Nano EasyDisperse™) can be used, as they are coated for easier dispersion.

Using the correct type of sunscreen for your base is crucial for achieving effective and even sun protection.