1. Does Lipstick Color Sit on Your Lips or Soak Into Them?
If you apply lipstick in front of a mirror and look again after a while, the color remains on your lips. When you gently press a tissue against them, some color transfers, but it does not all come off. This difference between "transferring color" and "remaining color" is thought to come from how the lipstick color is made.
There are two main ways of thinking about how color remains on lips. One is where particles of color (pigments) sit on the surface of the lips. Ordinary lipstick colors center on this method. The other is a color that dyes the lips, and products called "lip tints" explain that "dyes penetrate the lips to improve color retention."[1] The word "tint" means "to dye."
There is one more factor overlapping these. Lips are red before you apply anything. The color you see is the result of the applied color overlapping with the natural red base of the lips. This article looks at why color remains by examining the stick's contents, the dyeing colors, and lip skin in that order.
2. How Lipstick Sticks Are Made from Color Particles, Oil and Wax
A lipstick stick looks like a single solid block that is red all the way through when cut. However, stick-type lipsticks are generally made by kneading color-giving pigments and pearly substances that create shine into an oily base of waxes or liquid oils.[2] Lipsticks are made of an oil-based substrate and coloring agents, which include both pigments and dyes.[3]
The roles are divided. Wax acts as the framework that keeps the stick's shape; it is said that adding high-melting-point waxes like carnauba wax makes the stick stronger. Glossy types are said to have more oil, while matte types have more powder (fillers).[4] This is a general explanation found in English-language encyclopedias, but specific formulas vary by product.
Colors are made by combining multiple color materials like pigments or lake dyes. As a reference example, it is explained that pink can sometimes be made by mixing white titanium dioxide with red color materials.[4] This idea is similar to how mixing white and red paint creates pink.
Pigment particles are scattered within the base material and are thought to sit on top of the lips when applied. So, what exactly is a "soaking" color?
3. Why Are Dyes That Stain Lips Hard to Remove?
The "tint" in lip tint means "to dye." It is explained that dyes penetrate the lips, which improves how well the color lasts.[1] Because the lips themselves become colored, they are said to be resistant to time and rubbing.[5]
There is also an explanation that some products have formulas where dyes react with the pH of the lips to bring out a natural flush, in addition to pigments.[5] However, this is just one example from beauty media commentary. Formulas differ by manufacturer and product, so not all lipsticks work the same way.
Dyeing colors are not a new invention. A 1976 paper reported a method to separate and measure dyes used in lipstick (such as Eosin YS, Erythrosine, and Rhodamine B) using thin-layer chromatography.[6] Dyes have been one of the colors in lipstick for a long time. Old technical journals also mention formulas that use dyeing colors together with lake pigments like those used for pigments.[7]
The mechanism of how dyes remain on lips can be understood through the properties of Eosin, a red dye. Eosin binds like a salt to basic amino acids found in proteins, dyeing them red to pink.[8] Since the surface of lips is also made of protein, there is a possibility that lipstick dyes bind in a similar way. However, there is no source in this article that has confirmed this specifically for lipsticks; it remains an analogy.
So, what kind of skin are the lips that dyes soak into?
4. Why Lips Look Red Before Makeup: Thin Skin and Visible Blood Vessels
Lips are special skin on the body. Compared to cheeks, they have only a few layers of stratum corneum (the outermost skin layer), and they lack sebaceous glands and sweat glands.[9] Because the stratum corneum is thin, their protective power is weak, and they are explained to be prone to drying out.
Lips are red because the skin is thin, allowing the capillaries underneath to show through. It is said that melanin pigment is also very minimal.[10] In other words, lips are not a colored membrane but rather like a thin window where blood color is visible.
From this, the color of lips with lipstick applied can be thought of as an overlap of two colors: the applied color and the natural red base. The reason the same lipstick may look slightly different depending on the person or their health that day might be due to this overlap. However, this point has not been directly confirmed by sources; it is a speculation based on the concept of overlapping colors.
So, if you apply a thick layer of color on top of lips, does it transfer when rubbed against objects? How are researchers addressing this problem that lipstick faces?
5. What Problems Do Hard Films Have in Preventing Color Transfer?
A standard method for making long-lasting lipstick is to create a hard film on the lips using film-forming agents and volatile oils. However, this film is brittle and easy to peel off, making it difficult to keep color lasting long. There is also the challenge that lips tend to feel dry when the volatile oil evaporates.[11]
A paper published in 2022 in the Journal of the Society of Cosmetic Chemists reported that this problem could be improved by using a new cross-linked silicone resin.[11] This means that satisfying three conditions at once—low color transfer, resistance to peeling, and good application feel—was a challenge for researchers.
Looking at it this way, there are two main ways to "keep" lipstick color on lips: pressing it onto the surface with a film, or letting dyes soak into the lips themselves. Each method has its strengths and weaknesses, and it is thought that products carefully combine these approaches.
This paper is a report on one study and does not apply to all products.
6. Checking Color Overlap on Your Lips and Cheeks with Things at Home
Try comparing your own lips and cheeks in front of a mirror. Remember the explanation that the redness of lips comes from capillaries showing through thin skin below. If you mentally separate what makes up the color you see, the way lipstick looks might feel slightly different.
If you have a chance to go to a cosmetics counter with family, look for the word "tint." Reading package descriptions or labels can be a clue to finding words that explain how the color stays on.
Try layering colors with colored pencils. On white paper, use red and pink pencils. Layer pink over red, then red over pink, changing the order. Observe if the appearance changes depending on the layering order. This is to see that "how things look changes when colors overlap," not to verify how dyes work.