Vitamin C Serum Formulation Advice

Thank you for your follow-up questions regarding the Vitamin C serum formula you previously used. We understand you're looking for details on this formula to potentially recreate it. However, based on the ingredients you provided and the previous staff response, the original formula you received is problematic and does not follow good cosmetic formulation principles.

Let's address each of your questions in detail:

1. Ratio: It is impossible to determine the correct ratios from the list of ingredients provided. This list appears incomplete and highly questionable. Ingredient lists are typically ordered from highest to lowest concentration. The fact that Salicylic acid is listed first is highly unusual, as Salicylic acid is restricted to a maximum concentration of 2% in leave-on cosmetic products according to FDA regulations.
2. Type of Salicylic acid and Vitamin C (Ascorbyl palmitate) and Solubility:
   • Salicylic acid: Standard Salicylic acid does not dissolve directly in water. It dissolves well in organic solvents like alcohol or requires special techniques for use in water-based formulas. If you want to use Salicylic acid in a water-based serum, consider using water-soluble forms like Complex Salicylic Acid or Acacia Salicylic Acid.
   • Ascorbyl palmitate: Ascorbyl palmitate, or Vitamin C Ester, is an oil-soluble form of Vitamin C. It does not dissolve in water. To incorporate it into a formula where water is the main component, an Emulsifier is essential to help the oil and water phases mix and remain stable. This ingredient is missing from the formula you provided, which is another reason why the formula is likely unstable and unmixable as listed.
   • Furthermore, combining Salicylic acid with Ascorbyl palmitate in the same formula is not common practice and may not be ideal. Salicylic acid is typically used for exfoliation or acne treatment, while Ascorbyl palmitate is an antioxidant primarily effective in the oil phase. Combining them might reduce their individual effectiveness and create stability issues.
3. Ingredient Order: According to cosmetic labeling regulations, ingredients are listed in descending order of concentration. If the serum is primarily water-based, Water should be listed first. The fact that Salicylic acid is listed first is highly unusual and confirms that this formula is incorrectly presented.
4. Alternative Ingredients (Avoiding Oil and Preservatives):
   • Avoiding Oil: If you want a Vitamin C serum without oil, using oil-soluble Ascorbyl palmitate is not suitable. You should consider using water-soluble forms of Vitamin C instead, such as:
     • L-Ascorbic Acid: The pure form of Vitamin C, highly effective but unstable in water. It requires a low pH (around 2.0-4.0) and potentially stabilizers.
     • Ethyl Ascorbic Acid: A water-soluble, highly stable derivative of Vitamin C that is easy to use in water-based formulas.
     • Sodium Ascorbyl Phosphate (SAP) or Magnesium Ascorbyl Phosphate (MAP): Water-soluble, highly stable derivatives that are easy to use and suitable for formulas with a slightly higher pH (around 7-9).
   • Avoiding Preservatives: In any water-based cosmetic formula, using a Preservative is absolutely essential to prevent the growth of microorganisms like bacteria and fungi. Microbial contamination can cause the product to spoil quickly and pose a significant health risk to the user. Creating a water-based serum without a preservative is highly risky and unsafe. It is strongly recommended to use an appropriate preservative system at the recommended concentration to ensure the safety and shelf-life of your product.

Conclusion: The Vitamin C serum formula you provided has several issues regarding ingredients, solubility, and ingredient order, making it unsuitable for use. If you wish to create a Vitamin C serum, we recommend consulting reliable standard formulations and choosing a water-soluble form of Vitamin C if you want an oil-free serum. Always include a suitable preservative in water-based formulas for safety.

We hope this information is helpful. Please feel free to ask if you have any further questions.