Formulation Questions: Hyaluronic Acid, Preservative, pH, and Serum Application

Asked by: punika.thor On: October 24, 2017 Product Type: Cosmetics

Question

I have some questions about formulating a 100g serum:

  1. For a 100g formula, I need 0.5g of Hyaluronic Acid (Standard Molecule) and Hyaluronic Acid (Nano Molecule) combined. If I buy Double Hyaluron Liquid (10g size, containing 5% Hyaluron Standard and Nano), does this mean it contains exactly 0.5g of Hyaluron, sufficient for my formula? Can I replace the water portion with this 10g of Double Hyaluron Liquid?
  2. If I use 10g of Double Hyaluron Liquid, can I omit the preservative (Phenoxyethanol SA) 0.5% from the formula?
  3. I am concerned about the pH when adding Alpha Arbutin (pH 3.5-6.5) and the preservative Phenoxyethanol SA (pH 2.0-6.0) in the final step. My formula also contains Vitamin B3 (pH 6-7.5) and GlucoBright (pH 6-7). Should I test the pH before mixing these final ingredients, or should I add something to the formula to adjust the pH, and if so, in what quantity?
  4. Is Stabilized Vitamin C (Natural-C Glycol™) Serum a ready-to-use serum that can be applied directly to the skin?
  5. What is the correct application order and waiting time between applying Stabilized Vitamin C (Natural-C Glycol™) Serum and the serum from my custom formula?

Answer

Response to Your Formulation Questions

Here are the answers to your questions regarding the formulation, based on the information provided:

  1. Regarding Hyaluronic Acid Quantity: Yes, your calculation is correct. For a 100g formula, you need 0.5g of total Hyaluronic Acid (Standard + Nano). Using 10g of Double Hyaluron Liquid, which contains 5% Hyaluronic Acid, provides exactly 0.5g of Hyaluronic Acid. As confirmed, you can use the 10g of Double Hyaluron Liquid and adjust the amount of distilled water accordingly.

  2. Regarding Omitting Preservative: No, you cannot omit the preservative (Phenoxyethanol SA) when using Double Hyaluron Liquid. The preservative is necessary for the overall formula stability and safety. The recommended concentration for the preservative is at least 0.5-0.7% of the total formula.

  3. Regarding pH Concerns: There should be no significant issue with the pH for personal use. The final formula is expected to be slightly acidic to neutral (around pH 7). While some ingredients might be slightly outside their optimal pH range for maximum long-term stability (typically calculated for 2 years), they should still function effectively for a shorter period. If you are producing for commercial sale, it is recommended to measure the pH and adjust it downwards slightly if it is higher than 6 to ensure long-term stability.

  4. Regarding Mixing Order of Alpha Arbutin and Phenoxyethanol SA: The information provided indicates that both Alpha Arbutin and Phenoxyethanol SA are typically added in the final phase of mixing. However, a specific order between these two ingredients was not mentioned.

  5. Regarding Stabilized Vitamin C (Natural-C Glycol™) Serum: Yes, Stabilized Vitamin C (Natural-C Glycol™) Serum is a ready-to-use serum that can be applied directly to the skin.

  6. Regarding Application Order: It is recommended to use the Stabilized Vitamin C (Natural-C Glycol™) Serum and the serum from your formula at different times of the day (e.g., one in the morning and one in the evening). This is because Niacinamide (Safe-B3) in your formula can potentially interact with Vitamin C, leading to degradation of the Vitamin C.

Tags

Cosmetic Formulation Ingredient Interaction Preservation Serum pH Compatibility