Why Kojic Acid is Not Available in Tester Products

You've observed that while Kojic Acid is available for purchase, it's not an option in the product tester, and you noted its broad pH range. The staff's reply correctly points out that Kojic Acid is acidic and can affect other ingredients, requiring careful pH adjustment.

While Kojic Acid itself has a pH range where it can be effective (around 4-7), incorporating it into a pre-formulated base product, like those in a tester kit, presents challenges:

• Acidity: As the staff mentioned, Kojic Acid is acidic. Adding it to a finished product can lower the overall pH, potentially destabilizing other ingredients in the base formula that are sensitive to pH changes.
• Stability: Standard Kojic Acid (Kojic Acid) is known for its instability when dissolved in water, which can limit the shelf life of the final product. While Kojic Acid Dipalmitate is a more stable derivative and is oil-soluble, formulating with it still requires specific conditions (like heating to dissolve in the oil phase) that aren't feasible in a simple tester kit.
• Compatibility: Even within the acceptable pH range, Kojic Acid can interact with certain ingredients, potentially causing discoloration or reduced efficacy of either the Kojic Acid or the other ingredient. Ensuring compatibility across a range of potential base products and other added ingredients in a tester is complex.

Therefore, even though Kojic Acid has a functional pH range, the complexities of maintaining product stability, ensuring compatibility with various base ingredients, and the need for specific mixing methods (especially for the more stable Dipalmitate form) make it unsuitable as a simple add-in option in a general product tester. Formulating with Kojic Acid requires precise control over the entire formula composition and pH, which is best done during the full manufacturing process rather than in a simple mixing scenario like a tester kit.