Using Lactic Acid Neutralized (AHA) at pH 5.0: Exfoliation vs. Moisturizing Function

Yes, Lactic Acid (AHA) Neutralized (Deodorized) (Product ID 6376) can be used in a final product with a pH of 5.0.

Technical Analysis and Recommendations

1. Compatibility and Stability at pH 5.0:

   • This product is specifically designed to be a partially neutralized form of Lactic Acid, containing both Lactic Acid and Potassium Lactate. This adjustment makes it gentler and raises its inherent pH.
   • The product description states that a 10% concentration of this raw material in water has a pH of 4.0-4.5. Therefore, formulating a final product at pH 5.0 is perfectly acceptable and stable, as it is within the product's intended range of use for gentleness.

2. Functional Benefit at pH 5.0:

   • The primary function of the product at pH 5.0 will shift significantly towards moisturization and skin conditioning rather than strong chemical exfoliation.
   • Lactic Acid has a pKa of approximately 3.86. At pH 5.0, the majority of the Lactic Acid will be in its salt form (Lactate), which acts as a powerful humectant (a component of the skin's Natural Moisturizing Factor or NMF).
   • The exfoliation effect will be very mild, making it suitable for sensitive skin or daily use products where the focus is on hydration and gentle softening.

3. Additional Recommendations:

   • Use Rate: The recommended use rate for this raw material is 0.1-10%. Ensure you do not exceed this limit.
   • Exfoliation Goal: If your goal is to achieve a more noticeable exfoliation effect, the final product's pH should be adjusted closer to the product's inherent pH, such as pH 4.0-4.5. At this lower pH, a higher percentage of the Lactic Acid will be in its free acid form, maximizing its exfoliating potential while still benefiting from the gentleness of the neutralized form.
   • pH Adjustment: If you are formulating at pH 5.0, you may need to use a small amount of an acid (like Citric Acid or Lactic Acid 90%) or a base (like Triethanolamine or Sodium Hydroxide) to fine-tune the final pH after adding all ingredients, although the neutralized nature of this raw material makes pH adjustment less critical than with pure Lactic Acid.