Formulating Lightweight Water-in-Oil Sunscreen Gel

To create a lightweight sunscreen gel with your selected ingredients, here are the guidelines and recommended formulas.

1. Anhydrous Sunscreen Gel (Waterless Formula)

This formula uses your 4 selected ingredients to create a silky, matte-finish gel.

Recommended Ratio:

• Silicone Gel (Ultra Clear, Super Silky): 45-55% (Provides the silky base and matte look)
• SPF Protect Ultra™ III: 25% (Maximum protection)
• LipidSoft™ C1215: 15-20% (Helps dissolve the sunscreen and improves spreadability)
• Oil Thick™ Transparent: 2-5% (To adjust the thickness of the oil/sunscreen phase)

Mixing Method:

1. Mix LipidSoft™ C1215 and Oil Thick™ Transparent together. Heat to approximately 90°C until the powder is completely dissolved and the liquid is clear.
2. Allow the mixture to cool down to about 60°C, then add SPF Protect Ultra™ III. Mix well.
3. Gradually add this mixture into the Silicone Gel while stirring until a uniform gel texture is achieved.

2. Water-in-Oil (W/O) Sunscreen Formula

Your current 4 ingredients are all oil-phase components. To make a Water-in-Oil (W/O) emulsion, which is excellent for water and sweat resistance, you need to add a water phase and a W/O emulsifier.

Recommended Additions for W/O:

• Water-in-Oil EZ™: A W/O emulsifier to bind the water and oil/silicone phases.
• Magnesium Sulfate: To stabilize the W/O structure.
• Silicone Film (Trimethylsiloxysilicate): To significantly enhance water and sweat resistance.
• Water: To make up the remaining percentage.

Example W/O Ratio:

• Oil Phase:
  • Silicone Gel (Ultra Clear, Super Silky): 10%
  • SPF Protect Ultra™ III: 25%
  • LipidSoft™ C1215: 5%
  • Water-in-Oil EZ™: 3%
  • Silicone Film: 2%
• Water Phase:
  • Water: 53.5%
  • Magnesium Sulfate: 1%
  • Preservative: 0.5%

Answers to Your Specific Questions

• Can the sunscreen be added directly to a silicone base?
  Yes, SPF Protect Ultra™ III is oil-soluble and compatible with silicones. You can mix it directly into the Silicone Gel or a blend of Silicone Gel and LipidSoft™.
• Will 25% sunscreen provide the specified SPF?
  Yes. At 25%, it provides SPF approximately 70-100. While the test results were in an O/W system, using it at this concentration in an anhydrous gel or W/O system will still provide very high protection.
• How to make it Water/Sweat Resistant?
  The best way is to formulate it as a Water-in-Oil (W/O) system. Additionally, adding a film-forming agent like Silicone Film will create a durable layer on the skin that prevents the sunscreen from being washed away by water or sweat.

Important Note on Oil Thick™ Transparent: This ingredient requires high heat (90°C) to dissolve. Ensure it is fully dissolved in the LipidSoft™ before adding the sunscreen to avoid degrading the UV filters with prolonged high heat.