Botox, otherwise known as Botulinum Toxin Type A, is produced by the bacterium Clostridium botulinum. Botox works by blocking nerve signals in the muscles where it is injected. Without movement of these selected muscles in the face, certain wrinkles may be softened, reduced, or even disappear.
Botox only works on wrinkles that are caused by muscle movement. These are known as dynamic wrinkles and are often called "expression lines." Botox will not work on fine lines and wrinkles caused by sagging or loss of plumpness in the face, which are known as static wrinkles. The most common dynamic wrinkles that Botox can treat are lines on the upper face, such as the "11" between the brows, horizontal lines on the forehead and crow's feet around the eyes.