Formula Review: Exfoliating Body Moisturizer Texture, Preservation, and Cholesterol Solubility

Question

I am developing an exfoliating body moisturizer with a target pH of 5.5. My formula includes 4% Cholesterol. I am aiming for a fast-absorbing and non-greasy texture. I would like a review of my formula, specifically regarding: The need for a preservative and suitable options. How to achieve the desired fast-absorbing, non-greasy texture, considering the high Cholesterol content. The solubility of 4% Cholesterol in the formula. Any other essential ingredients or adjustments needed to achieve the target pH and overall stability/performance.

MySkinRecipes Expert · Accepted Answer

Subject: Formula Review for Exfoliating Body Moisturizer

Thank you for submitting your formula for review. Based on your desired properties (exfoliating, moisturizing, fast absorption, non-greasy) and target pH 5.5, here is a review incorporating feedback:

Preservative: A preservative is essential for product stability and safety, even when stored in the refrigerator. As recommended, consider adding Mild Preserved Eco at 1%. This preservative is considered gentle and its components are not classified as preservatives by the FDA in Thailand, which might be beneficial for claims.
Texture (Fast Absorption, Non-Greasy): Achieving a fast-absorbing, non-greasy texture will be challenging with Cholesterol at 4%. As noted, this high percentage of Cholesterol will likely result in a sticky or heavy feel. While ingredients like Light Cream Maker, LipidSoft Lite, Isopentyldiol, and DMI help with texture and dissolution, they may not fully counteract the greasiness from 4% Cholesterol. Adding silicones might help with slip but won't eliminate the inherent feel of high Cholesterol and may raise concerns about clogging, as you mentioned.
Cholesterol Solubility and Oil Phase Percentage: Dissolving 4% Cholesterol requires a sufficient amount of oil/ester phase or high processing temperatures, which could potentially degrade heat-sensitive ingredients like Papain or Retinal. It is recommended to reduce the Cholesterol concentration to 1-2% to ensure easier dissolution and potentially improve texture without needing excessive heat or oil phase components solely for solubility. The current 3% fatty acid/oil phase components intended for dissolving Cholesterol might be insufficient for 4% Cholesterol without high heat, or reducing Cholesterol is the preferred method to avoid this issue.
Other Essential Ingredients:
- pH Adjustment: To achieve the target pH of 5.5, you will likely need to adjust the pH of the final formula using an appropriate acid or base. The amount needed will depend on the final mixture.
- Chelating Agent (e.g., EDTA): While not explicitly mentioned in the feedback, a chelating agent like EDTA is often included in cosmetic formulations to improve stability by binding to metal ions. Consider adding a small percentage if stability is a concern, although it wasn't highlighted as critical feedback in this specific review.

Summary:

Add a preservative (e.g., Mild Preserved Eco 1%).
The high concentration of Cholesterol (4%) will likely make the product feel sticky/greasy, making it difficult to achieve a fast-absorbing, non-greasy texture.
Consider reducing Cholesterol to 1-2% for better solubility and texture.
Adjust the final pH to 5.5.
Consider adding a chelating agent for stability.