Ingredient Compatibility and Stability Issues with Silky Serum Base

Question

When formulating a serum using Silky Serum Base, I encountered issues where the serum becomes liquid or separates after adding certain ingredients. I have several questions regarding this: What specifically causes the "self-emulsifying" property in some active ingredients? Does it involve specific solvents or chemical modifications? What kind of solvents are typically used to dissolve these active ingredients? Regarding ingredients like Hydrolyzed Protein and Aloe Vera Extract, do they contribute to the "self-emulsifying" effect, or is their impact on texture (like making the serum more liquid) due to other reasons? I observed issues when adding ingredients identified as having self-emulsifying properties, such as Hi-EGCG™ (Green Tea Extract), Licorice Extract (Licochalcone A), Hi-Quercetin®, WhiteCumin™ 2x, and Activated Resorcinol™ S. My attempts resulted in the serum becoming liquid when adding these ingredients. Can ingredients with self-emulsifying properties be included in a Silky Serum Base formulation at a certain concentration limit, or should they be avoided entirely when using this base?

MySkinRecipes Expert · Accepted Answer

Understanding Serum Stability Issues

Based on the detailed information you provided and the responses from the staff, the issues you encountered with your serum formulations using Silky Serum Base / Plus becoming liquid or separating are primarily due to ingredient incompatibilities.

Self-Emulsifying Ingredients

The staff identified several ingredients that have "self-emulsifying" properties. This means they contain components (like solvents and/or emulsifiers added by the supplier) that help them disperse, but these components can interfere with the primary emulsifier system of the Silky Serum Base.

What causes the self-emulsifying property? It's a combination of the active ingredient, its solvent, and often an emulsifier added by the raw material supplier to make the active ingredient compatible with different formulation types. The exact solvents used are typically proprietary.
Problematic Ingredients: The ingredients identified by the staff as having this incompatible self-emulsifying property are:
- Hi-EGCG™ (Green Tea Extract)
- Licorice Extract (Licochalcone A)
- Hi-Quercetin®
- WhiteCumin™ 2x
- Activated Resorcinol™ S

When these ingredients are added to a formula based on Silky Serum Base, their self-emulsifying components can disrupt the base's emulsification system, leading to thinning or breaking.

Usage Recommendation: As the staff indicated, it is generally not recommended to use ingredients with these incompatible self-emulsifying properties in formulations primarily based on Silky Serum Base or Silky Serum Base Plus. Even at low concentrations, they can destabilize the emulsion.

Other Ingredients Causing Thinning

You also noted thinning with Hydrolyzed Protein and Aloe Vera Extract.

Hydrolyzed Protein: The staff clarified that Hydrolyzed Protein is water-soluble and does not cause self-emulsification issues. If thinning occurred, it's likely due to other factors in the formula, not an emulsification conflict.
Aloe Vera Extract: The staff explained that Aloe Vera Extract naturally contains electrolytes. Electrolytes can interfere with the viscosity and stability of certain gelling agents and emulsifiers, causing thinning. This is a known compatibility issue with some thickeners and emulsifiers, not related to self-emulsification in this case.

Lactic Acid and pH Adjustment

Thinning and separation after adjusting pH with Lactic Acid (as seen in Formula 2) can occur because pH changes impact emulsion stability. The staff recommended dissolving Lactic Acid in the water phase initially, which is good practice. The separation suggests the final pH or the addition method destabilized the emulsion.

Summary

The main reasons for your formulation issues are the incompatibility of certain active ingredients with self-emulsifying properties with the Silky Serum Base, and the impact of electrolytes from ingredients like Aloe Vera Extract on viscosity. To ensure stable serums with Silky Serum Base / Plus, avoid ingredients with incompatible self-emulsifying properties and be mindful of electrolyte-containing extracts and pH adjustments.