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Lipsticks are designed to improve the natural appearance of lips. They typically involve a color change but also increase shine and smooth out the appearance of wrinkles and folds on the lips. They are a solid stick product housed in a molded packaging.
What lipsticks do
When lipsticks are applied, a waxy product film is left behind on the lip surface. The color components of the lipstick block the natural surface color, changing it while the film components help keep the color attached to the lips.
How lipsticks work
Lipsticks are made from hydrophobic materials. When the solid formula is applied to the lip surface, friction melts it briefly and allows for transfer. The material cools and re-forms creating a film that sticks to the surface due to hydrophobic interactions. In addition to the hydrophobic base, color is another key ingredient in lipstick. The color reflects light of a certain wave length to give the impression of a new color on the surface. Silicones and oily materials are also added to reflect light and provide shine.
The main ingredients in a lipstick include a solidifier, diluent oils and colorant. Typcial solidifiers include waxes such as Beeswax, Carnauba Wax or Candelilla wax. Diluent oils are used to help evenly disperse colorants. Examples include castor oil or jojoba esters. Finally, colorants are included in lipsticks including organic colorants such as Red 7 or inorganic colorants like Red Iron Oxide.
A variety of other ingredients are added to lipstick formulas to modify the melting characteristics, the adhesion profile, stability and make production easier.