Appropriate pH for Mandelic Acid Solutions

Based on the information provided, the appropriate pH for a facial formulation containing Mandelic Acid, whether at 10% or 30% concentration, must comply with the Thai FDA (อ.ย.) requirement that the pH should not be lower than 3.5.

It is crucial to understand that the final pH of your solution is influenced by all ingredients in your formulation, not just the concentration of Mandelic Acid. Therefore, you cannot determine the final pH based solely on the percentage of Mandelic Acid used.

Recommendation:

Always measure the pH of your finished formulation using a pH meter to ensure it is within the acceptable range (not below 3.5) before applying it to the skin. This is the most accurate way to know the true pH of your product.