LHA Serum Formulation Adjustment

Regarding your LHA serum formulation and the issues you're experiencing:

• Replacing HPMC with Hydroxyethyl Cellulose (HEC): Yes, you can replace HPMC with Hydroxyethyl Cellulose. Based on the discussion, using Hydroxyethyl Cellulose is recommended if you want to achieve a clear serum texture, as some other gelling agents like certain pro polymers can result in a milky appearance.

• Addressing Cloudiness and Improving Skin Penetration: The issue of the serum becoming cloudy after a month and the goal of improving skin penetration can be addressed by adding Ethoxydiglycol to your formula. Ethoxydiglycol acts as both a solvent and a penetration enhancer, helping to keep ingredients dissolved and improving their absorption into the skin. This can help prevent the cloudiness issue and enhance the effectiveness of the LHA and Hyaluronic Acid.

  The suggested usage rate for Ethoxydiglycol to improve penetration is potentially up to 20%. However, please note the current FDA usage limit for leave-on products is not more than 2.6%. Always check the latest regulations before finalizing your formulation.

• Impact on Texture and Properties: Replacing HPMC with Hydroxyethyl Cellulose will primarily affect the texture, aiming for a clear gel. Adding Ethoxydiglycol will affect the solubility of ingredients (helping prevent cloudiness) and improve skin feel and penetration without causing precipitation if used within recommended guidelines.

In summary, modifying your formula to use Hydroxyethyl Cellulose as the gelling agent and incorporating Ethoxydiglycol can help you achieve a clear, stable serum with improved skin penetration for your LHA and Double Hyaluron Liquid ingredients.