pH Adjustment for Your Formula

Regarding your formula and the concern about pH affecting EGCG, the staff's assessment is correct. Your formula is likely to have a pH in the range of 6.5-7.

Green Tea Extract (EGCG) is most stable and effective in a slightly acidic environment, ideally between pH 5.5 and 6.5. A pH above this range can reduce its efficacy.

To ensure your formula is within the optimal pH range for EGCG, you should adjust the pH downwards. As the staff suggested, you can use acidic ingredients such as:

• Lactic Acid
• Glycolic Acid
• Citric Acid
• Gluconolactone (a type of PHA)

You can add the pH adjusting ingredient to the water phase before combining it with the oil phase, or you can adjust the pH after the cream has fully formed. Adjusting after forming the cream might make pH measurement slightly more challenging.

To adjust the pH, measure the pH of your finished formula using a pH meter or pH strips. Add the chosen acidic ingredient drop by drop, stirring well after each addition, and re-measure the pH until it falls within the desired range of 5.5-6.5.