Principles of Formulating Creams with Hyaluronic Acid

Hyaluronic Acid (HA) is a popular ingredient in creams and skincare products due to its excellent moisture-retaining properties. The key principles for incorporating HA into cream formulations are as follows:

How Hyaluronic Acid Works

Hyaluronic Acid is a hydrophilic substance that functions best in the water phase of a formulation. Therefore, it is typically added to the water portion before mixing with the oil phase to create a cream.

Types of Hyaluronic Acid and Their Functions

Hyaluronic Acid comes in various molecular sizes, each with different properties and functions:

• Small Molecule: Can penetrate deeper into the skin, providing hydration from within. It does not significantly contribute to gel formation or film-forming on the surface.
• Standard Molecule and Large Molecule: Cannot penetrate deep into the skin but form a thin film on the outer layer, acting as a barrier to prevent water loss. This makes the skin appear plump, hydrated, and smoother. Large molecules create a better gel texture than standard molecules.
• Specialized Hyaluronic Acid Types:
  • Hyaluronic Acid Elastomer (Hyacross Gel): A cross-polymer form with a thick gel texture, highly effective at retaining moisture for extended periods and excellent at forming a protective film on the skin.
  • 4D Hyaluronic Acid: A combination of multiple HA molecular sizes (small, medium, large, and cationic) to provide comprehensive hydration across all skin layers. It creates a 3D network that helps retain water from both external and internal sources.
  • HyaOil™ (Oil-Dispersed Hyaluronic Acid): HA dispersed in oil, suitable for oil-based formulations like lipsticks and lip balms, providing hydration and conditioning to the lips.

Incorporation into Formulas

• Powdered Hyaluronic Acid types (e.g., Standard Molecule, Small Molecule, Large Molecule) must be dissolved in water first. This can be done by shaking and refrigerating or by using a high-speed blender.
• Liquid or gel forms of Hyaluronic Acid (e.g., 4D Hyaluronic Acid, Hyaluronic Acid Elastomer, Hyaluronic Acid Gel Base) can be added directly to the water phase.
• The optimal pH range for most Hyaluronic Acid types is between 3.0-9.0 and the temperature should not exceed 70 degrees Celsius during processing.

Other Ingredients in HA Cream Formulas

In addition to HA, which is a humectant (water-attracting agent), a good cream formula should include other ingredients to enhance performance:

• Emollients: Such as various oils and esters, help soften and smooth the skin's surface and reduce water loss.
• Occlusives: Such as Petrolatum, Mineral Oil, and Silicones, create a protective film on the skin to prevent water evaporation.
• Emulsifiers: Help to blend the water and oil phases into a stable cream texture.
• Preservatives: Crucial for water-based formulas (e.g., Phenoxyethanol) to prevent microbial growth, which can degrade Hyaluronic Acid and cause a loss of viscosity.

Recommended Usage Rates

General usage rates for HA in cosmetics are typically 0.1-0.5%. Higher concentrations (0.3-0.5%) may be used for very dry skin, while lower concentrations (0.05-0.1%) might be sufficient for normal or slightly dehydrated skin. Specialized forms like 4D Hyaluronic Acid may have higher recommended usage rates (e.g., 2-20%) depending on the specific product type and desired concentration.

Understanding the properties of each type of Hyaluronic Acid and how they interact with other ingredients will help you develop a cream formula tailored to specific skin needs.