Emulsifier and Silicone Compatibility, Stability, and Texture in Cosmetic Formulations

Question

I have several questions regarding cosmetic formulation, specifically concerning emulsifiers, silicones, and their impact on stability and texture:

Can Silk Lotion Maker emulsify a formula with high electrolyte content, such as 10% Hyaluronic liquid + 5% B5 (with possibly only 1-2% oil)? Is it necessary to use Magnesium Sulfate to increase stability in such a formula?
For a lightweight formula like a spray or one with low viscosity (potentially without any gelling agents), the team suggested using Silk Lotion Maker 2-3% together with Polysorbate 80 1%. If I change this to using Silk Lotion Maker 3% together with Light Lotion Maker 1-2% instead, is this possible? And will it affect separation if the formula contains a total of 30% oil + silicone?
Theoretically, some types of silicone can coat the skin. If I use two products consecutively (layered), for example, applying the first formula containing Trisiloxane + water solution, and then applying a second formula with the same composition as the first, will the silicone in the first formula interfere with or hinder the absorption of the water solution in the second formula?
For a serum formula that is lightweight, easy to spread, and fast-drying, which product is most suitable among Trisiloxane, Dimethicone 1Secs, and SiliconeGel (Ultra Clear)? Also, is SiliconeGel (Ultra Clear) a volatile type of silicone?

MySkinRecipes Expert · Accepted Answer

Cosmetic Formulation Questions

Here are the answers to your questions regarding cosmetic formulation:

1. Silk Lotion Maker and Electrolytes

Silk Lotion Maker (Bis-PEG/PPG-16/16 PEG/PPG16/16 Dimethicone) is an oil-in-water emulsifier suitable for creating light textures and sprays, capable of emulsifying up to 30% oil. While it can handle low oil percentages, high concentrations of electrolytes like 10% Hyaluronic Acid liquid and 5% Vitamin B5 can be challenging for many O/W emulsifiers and may affect stability. The product description does not specifically guarantee stability with high electrolyte levels.

Magnesium Sulfate is typically used as a stabilizer in water-in-oil emulsions and is generally not suitable for oil-in-water formulas, which your proposed formula (high water-soluble actives, low oil) appears to be. Therefore, Magnesium Sulfate would not be needed and is not recommended for stabilizing this type of formula.

2. Alternative Emulsifier Combination for Light Formulas

For a light formula like a spray or low-viscosity serum with up to 30% oil + silicone, the combination of Silk Lotion Maker (2-3%) and Polysorbate 80 (1%) is specifically recommended in the product descriptions for achieving a sprayable consistency.

Using Silk Lotion Maker (3%) with Light Lotion Maker (1-2%) instead of Polysorbate 80 is not a standard recommended pairing in the product descriptions. While both are O/W emulsifiers suitable for light textures, combining different primary emulsifiers can impact emulsion stability, especially with a significant oil/silicone phase (30%). Stability testing would be essential if you choose this combination, as separation is possible.

3. Silicone Film and Absorption

Trisiloxane is a volatile silicone, meaning it evaporates quickly after application. While silicones can form temporary films, the film from a volatile silicone like Trisiloxane is not persistent. Therefore, applying a formula containing Trisiloxane followed by a second formula with water-soluble ingredients is unlikely to significantly hinder the absorption of the water-soluble components from the second layer once the Trisiloxane has evaporated from the first layer.

4. Best Silicone for Light, Fast-Drying Serum

For a light, easy-to-spread, fast-drying serum, both Trisiloxane and Dimethicone 1Secs are suitable due to their volatile nature and ability to provide a lightweight feel and fast drying. Dimethicone 1Secs is noted for having the fastest evaporation rate among the volatile silicones mentioned.

Silicone Gel (Ultra Clear) provides excellent spreadability and a soft, silky feel but is not a volatile silicone. It will not evaporate quickly and therefore will not contribute to a fast-drying effect. It is more suitable for improving texture and feel rather than promoting rapid drying.

Therefore, for a serum emphasizing fast drying, Dimethicone 1Secs or Trisiloxane would be the most appropriate choices. Silicone Gel (Ultra Clear) is not volatile.