Technically, Onabotulinum A is a toxin originally from bacteria. In massively diluted commercial preparations like Botox, it acts as a muscle weakener. Certain muscles of the face act to produce deep creases in the overlying skin. In some areas of the face, Botox greatly reduces the appearance of those wrinkles. Commonly, between the eyebrows, crow’s feet, and forehead are treated. Measured in units, most areas receive 10 to 30 units, depending on the extent and thickness of the muscle to be treated.