pH Adjustment and Efficacy of Whitening Cream
Question
I made a whitening cream formulation that resulted in a high acidic pH. Can I use TEA to increase the pH to a normal range? Will the whitening efficacy still be present after adjusting the pH? What is the typical/appropriate pH range for whitening creams?
Answer
Subject: Regarding pH in Whitening Cream
Hello,
Thank you for your question.
Using TEA to adjust pH: Yes, Triethanolamine (TEA) is a common alkaline ingredient used in cosmetic formulations to increase pH (make it less acidic or more alkaline). So, you can use TEA to raise the pH of your acidic whitening cream.
Effect on whitening efficacy: Adjusting the pH can potentially affect the efficacy and stability of the whitening agent(s) in your cream. Many active ingredients, including whitening agents, are sensitive to pH. Some work best at a specific pH range, and changing the pH outside this range can reduce their effectiveness or cause them to degrade. The impact depends entirely on the specific whitening ingredient(s) you are using.
Normal pH for whitening creams: There isn't a single "normal" pH for all whitening creams. The optimal pH depends heavily on the active whitening ingredient(s):
- For example, formulations containing L-Ascorbic Acid (Vitamin C) are often formulated at a low pH (around 2.5-3.5) for stability and absorption.
- Other common whitening agents like Niacinamide, Alpha Arbutin, or Kojic Acid are often formulated at a pH closer to the skin's natural pH (around 4.5-5.5) or slightly higher (up to 7).
- Generally, cosmetic creams are formulated to be compatible with the skin's natural pH (4.5-5.5) to minimize irritation, but this can be adjusted based on the requirements of the active ingredients.
Therefore, while you can use TEA to adjust the pH, it's crucial to consider the specific whitening ingredients in your formula and how they are affected by pH changes. Ideally, any pH adjustment should be followed by stability and efficacy testing.
Hope this helps!
Best regards.