cosmetics_29052012

Article by: Kelly Dobos

Eosine dyes used in cosmetic literally stain the skin, producing a blue red/tint. Incorporated at low level they can add to long-wear properties of lipstick. These stains were the basis for the low cost mood lipsticks of the 70s and their use is becoming popular again with sophisticated lipsticks, glosses, and even blush.

cosmetic colors

Bright shades of aluminum lake pigments with low opacity are used to impart color to the stick with out significant pay-off, or color on application to the skin. If other pigments are used, they should be used in amounts that will not provide a covering effect upon application.

The eosine dyes do not affect the visual color of the stick but as they are able to stain the skin they will leave a color on application, which is difference from the visual color of the stick. The dyes react with skin pH to create some color variation from person to person. A small amount of citric acid can be used if no coloration of the stick or base is needed.

Below is an example of a formulation for a lipstick that is green but turns pink in the lips.

color changing lipstick formula

Procedure:

Premix pigments and citric acid into sufficient castor oil (Part A) and disperse through a 3-roll mill twice. Mix and melt all wax and oil ingredients (Part B), heating to 80 – 85°C. Mix in preservatives (Part C) until fully dispersed. Add pre-milled pigments, citric acid, and castor oil (Part A). Mix until homogeneous. Cool batch to 55 – 60°C and pour into molds.

Kelly Dobos

About the Author

Kelly Dobos

Kelly Dobos is a cosmetic chemist and expert in both skin care and make-up product formulation. She has the coolest job and a passion for teaching others the smartest ways to express their creativity through cosmetic chemistry.

6 comments

  1. Jolie

    Thank you, Kelly.
    Such a great thing to know about eosine dyes. Now I’ve learned how it works.
    How about the clear gel stick? I mean what kind of wax we use for the lipstick base ?

  2. Jolie

    Hi Kelly,
    I usually use Red 21 & Red 27 for my lipstick. Actually, I didn’t know that those are eosine dyes because they always show visual colors.
    So do you mean that, by adding citric acid those dyes would become transparent (do not affect to visual color)?
    And if we adjust the pH downward (by adding more citric acid), the no-color stick would turn to transparent gel-stick ?

    1. Kelly
      Kelly

      Lowering the pH will cause the color to disappear, the eosine dyes act like pH indicators.

  3. Jolie

    Hi Kelly,
    Thank you for the article. Exactly what I want to learn.
    I have 2 questions
    1/ Except for Red No.21 & 27, is there anything else used as eosine dye ?
    2/ There’s a transparent lipstick (like a gel stick) which shows color when being applied to lip. Do you know how to make it ?
    Thank you .

    1. Kelly Dobos
      Kelly Dobos

      The only other one listed by the FDA is Orange 5. You would need to adjust the pH downward with citric acid to for a gel stick to appear clear. Hope this helps.

  4. Jolie

    Hello Kelly.
    Thank you for this useful article.
    I would like to learn if there’s any colorant else used as eosine dyes except for Red21 and Red 27.
    And could you tell me about how to make a transparent l lipstick which will change to red color when being applied to lip ?

Leave a Reply

Your email address will not be published. Required fields are marked *