Botulinum toxins used for injections are complex proteins produced by Clostridium Botulinum Type A which is a type of bacteria.  When injected locally in very small amounts into the muscles temporarily blocks the nerve signals that tell it to move.  When injected into specific facial muscles producing wrinkles, they relax and the face appears smooth and wrinkle-free. This effect is temporary and may last anywhere between 3 and 4 months depending on many factors such as the level of activity of the client, speed of metabolism, where it is injected etc.