Serum Formulation: Compatibility, Emulsifiers, and Oily Skin

Hello,

Regarding the serum formula you provided:

• Horse Oil 3%
• Repair Activator 10%
• Alpha Arbutin 2%
• Zinc PCA 1%
• Tomato Extract 5%
• Vitamin B3 5%
• GlucoBright 4%
• Distilled Water 20%
• Tween20 (percentage asked)
• Pro Polymer 0.8%
• Nature Preserve 1.25%

And your questions about compatibility, Tween20 percentage, and replacing Tween20/Pro Polymer with Light Cream Maker.

Here is an analysis:

1. Compatibility: The formula contains both oil-based ingredients (Horse Oil) and water-based ingredients (most others, including extracts, vitamins, peptides, Zinc PCA). To combine these into a stable serum, an emulsifier like Tween20 is necessary. So, physically, they can be made compatible with an emulsifier.
2. Ingredient Conflict for Oily Skin: As the staff mentioned, if the serum is for oily skin, the combination of Horse Oil (a relatively heavy oil that adds moisture/oiliness) and Zinc PCA (an ingredient for oil control) is counterproductive. Using a heavy oil like Horse Oil is generally not recommended for oily skin types.
3. Tween20 Percentage: The amount of Tween20 needed depends on the amount of oil (3% Horse Oil) and the desired texture and stability of the emulsion. There isn't a single fixed percentage; it typically requires testing to find the optimal amount to effectively emulsify or solubilize the oil phase within the water phase.
4. Light Cream Maker Replacement: A suitable "Light Cream Maker" ingredient could potentially replace both Tween20 (as an emulsifier) and Pro Polymer (as a thickener) if it is designed to create a serum or light cream texture and can effectively emulsify the oil phase in your formula. However, this depends on the specific Light Cream Maker product's properties.
5. Adding Kojic Acid Dipalmitate and Mineral Oil: You asked about adding Kojic Acid Dipalmitate and Mineral Oil. Kojic Acid Dipalmitate is oil-soluble, so adding an oil like Mineral Oil (as you suggested) would be necessary to dissolve it. However, adding more oil (Mineral Oil) would further increase the oiliness of the formula, which is not ideal for oily skin, reinforcing the conflict mentioned in point 2.

Given your skin type is oily, the staff's suggestion to remove the oil phase (like Horse Oil) and focus on water-soluble ingredients suitable for oil control and brightening/anti-aging (as shown in their revised formula) is a good approach for creating a serum that is less likely to feel heavy or contribute to oiliness.