Comparing Penetration Enhancers for Oily Skin

Based on the information provided, here is a comparison of the substances regarding their effectiveness as penetration enhancers, particularly for oily skin:

It's important to note that the best penetration enhancer depends on the overall formula and the user's skin type. However, we can compare the characteristics of each substance:

• PE-1 Aqua: This is specifically designed for formulas containing water-soluble active ingredients. If your active ingredients are water-soluble and your formula is water-based (common for oily skin to avoid oiliness), PE-1 Aqua is likely the most effective choice for enhancing their penetration. Its effectiveness decreases if used with non-water-soluble actives.
• 1,2-Hexanediol: This substance can help enhance penetration for various types of ingredients. However, for water-soluble ingredients, its penetration enhancement capability is generally not as strong as PE-1 Aqua. It also offers the benefit of acting as a preservative.
• Ethoxydiglycol: This substance has characteristics similar to 1,2-Hexanediol regarding its function as a carrier or solvent that can aid penetration.
• Pro Polymer: This is primarily a gelling agent used to create gel textures. While the gel texture it forms can help the product absorb well into the skin compared to other gelling agents, it does not function as a direct penetration enhancer in the same way that PE-1 Aqua, 1,2-Hexanediol, or Ethoxydiglycol do by interacting with the skin barrier or solubilizing actives.

Conclusion for Oily Skin:

For oily skin, formulations often focus on water-based ingredients and avoid oils. Since many active ingredients suitable for oily skin (like some forms of Vitamin C, Hyaluronic Acid, etc.) are water-soluble, PE-1 Aqua is generally the most recommended substance among those listed for enhancing the delivery of these actives into the skin. This is because it is specifically optimized for water-soluble substances in water-based systems, which are typical for oily skin care.

While 1,2-Hexanediol and Ethoxydiglycol can also aid penetration, PE-1 Aqua is likely more effective for water-soluble actives commonly used for oily skin. Pro Polymer's benefit is more about the texture and overall absorption of the gel formula rather than directly enhancing the penetration of specific active molecules through the skin barrier.