Using Color Changing Pigment (D&C Red 21) in Anhydrous Balm Stick
Question
When using D&C Red 21 Color Changing Pigment in an anhydrous balm stick formula, is pH control necessary for the color change to occur? Also, what medium should be used to dissolve this pigment in an anhydrous formula?
Answer
Using D&C Red 21 Color Changing Pigment in Anhydrous Formulas
Regarding the use of D&C Red 21 Color Changing Pigment (CI45380) in an anhydrous balm stick formula:
pH Control: You do not need to control the pH of the anhydrous formula itself for this pigment to change color. D&C Red 21 is designed to change color upon contact with the skin, reacting to the skin's natural pH. The color change happens when the anhydrous product is applied and interacts with the moisture and pH on the skin surface.
Dissolving Medium: This pigment dissolves in a variety of oils. This makes it suitable for use in anhydrous formulas like balm sticks, which are primarily composed of oils and waxes.
In summary, for a balm stick using D&C Red 21, focus on dissolving the pigment properly in the oil phase of your formula. The color change will occur automatically when the product is applied to the skin due to the skin's pH.
