Mixing Ingredients with Different pH and Adjusting for Skin

Hello,

Here are the answers to your questions about pH:

1. Mixing substances with different pH values: When you mix substance A (pH 3-4) with substance B (pH 4-6), the resulting pH of the mixture will be somewhere between the pH values of the two substances. The final pH will depend on several factors, such as the concentration of each substance and their buffering capacity, which helps resist changes in pH. Complex calculations are not typically necessary for cosmetic formulation. Generally, the resulting pH will fall within the range of the two starting pH values.
2. Adjusting pH to be suitable for the skin: If the pH of your mixed product is too high or too low for the range suitable for the skin (skin typically has a pH of around 4.5-5.5), you can adjust the pH by adding pH adjusters.
   • To lower the pH (make it more acidic): You can use mild acidic substances like Citric Acid, Lactic Acid, or Glycolic Acid in small amounts.
   • To raise the pH (make it more alkaline): You can use mild alkaline substances like Sodium Hydroxide or Triethanolamine (TEA) in small amounts.

Adjusting pH should be done carefully and gradually, using a pH meter or pH strip to check the pH after each addition of the pH adjuster.

Hope this answer is helpful!