Stability and Preservation of Liquid Skin Brightening Formula with Soy Extract

Regarding your proposed formula for skin brightening:

Based on the staff's feedback, the formula as written (liquid with Soy Extract) may have stability issues, specifically precipitation of the Soy Extract.

• Formula Acceptability: The staff mentioned that Soy Extract requires a thicker base (gel or cream) to prevent it from settling out.
  • If you want to keep the formula as a liquid, you should remove the Soy Extract.
  • If you want to keep the Soy Extract, you would need to change the formula to a gel or cream consistency. The staff provided a link for beginners on how to create gel or cream formulations.
• Preservative: Yes, you absolutely need to add a preservative to this formula. Any water-based cosmetic product is susceptible to microbial growth, even when stored in the refrigerator. Refrigeration slows down growth but does not stop it entirely or protect against contamination during use. Adding a suitable broad-spectrum preservative is crucial for the safety and shelf-life of your product.

The percentages you've chosen for the other ingredients seem reasonable, but the primary concern with the current formula is the stability issue with the Soy Extract in a liquid base and the lack of a preservative.

Please let me know if you'd like to explore options for creating a gel or cream base to include the Soy Extract, or if you'd like suggestions for suitable preservatives.