Formula for Melasma Reduction and Skin Whitening Gel

Regarding your question about the compatibility of ingredients and the pH level in your gel formula for melasma reduction and skin whitening:

Your concern about the pH stability of Alpha Arbutin is valid. Alpha Arbutin is most effective and stable in a pH range of 3.5-6.5. At pH levels above 7, it can potentially hydrolyze into hydroquinone, which is an undesirable substance.

Based on the ingredients you've listed, including Azelaic Acid, Tranexamic Acid, N-Acetyl, Vitamin B3, and Natto Gum, the final pH of your formula is estimated by the staff to be around 7. While this is close to the threshold for Alpha Arbutin stability, it is recommended to verify the actual pH.

Recommendation for pH Adjustment:

• It is crucial to measure the pH of your mixture before adding the Pro Polymer. You can use pH paper for a quick check.
• The goal is to ensure the pH is below 7 to maintain the stability of Alpha Arbutin.
• If the measured pH is around 7 or higher, you can carefully lower it by adding a small amount of an acidic ingredient. As suggested, Citric Acid or Lactic Acid are suitable options for adjusting the pH downwards.
• Add the acid drop by drop, mixing thoroughly, and re-measure the pH until it is within the desired range (ideally below 7, and within the optimal range for Alpha Arbutin if possible, while considering the pH requirements of other ingredients).

Recommendation for Gel Texture:

• The staff also noted that a high concentration of Azelaic Acid (10%) might result in a soft gel texture.
• To achieve a better consistency, they recommend increasing the concentration of Pro Polymer slightly, suggesting a range of 1.5% to 2.0% instead of 1%.

By measuring and adjusting the pH as needed and optimizing the Pro Polymer concentration, you can improve the stability and texture of your melasma reduction and skin whitening gel.