If you keep in mind highschool chemistry class, you may keep in mind utilizing litmus paper to research the pH degree of assorted substances (per BBC Science Focus). Similar to how litmus paper modifications shade relying on the pH degree, the dyes utilized in color-reacting lipsticks additionally act as an indicator. Basically, the dyes within the merchandise change shade as a response to your pores and skin’s pH (by way of make-up.com by L’Oreal).
Cosmetic chemist Ni’Kita Wilson instructed Allure that the first magical dye utilized in color-changing merchandise is none aside from Red 27. “Red 27 is pH-driven. When it is available in contact with moisture, the change in solubility and pH causes the dye to show vibrant pink,” Wilson defined. According to BBC Science Focus, the dyes used within the merchandise are weak acids that seem colorless. Since the pH ranges of the lips will likely be increased (much less acidic) than the lipstick, a chemical response happens which turns the clear, weak acid right into a bright-colored product.
Wilson added that the Red 27 dye stays colorless when it stays unexposed to water. Therefore, the dye might be blended into an emollient make-up product primarily based on oil or wax — like a lipstick — and stay clear. Per make-up.com, the clear, pH-reacting substance can be blended in with one other shade. That’s how the color-changing lipsticks of the Eighties got here in vibrant neon colours that every one turned pink on the lips.