There are eight type of Clostridium Botulinum, each of which produces a different type of neurotoxin. There are three common types of Botox used, types A, B and E, in medical and cosmetic procedures. All types contain similar properties; the minor difference in the types of neurotoxins produced will dictate which part of the acetylcholine complex is disrupted. The effect of paralyzing the muscle is the prevention of contractions that cause and deepen wrinkles in the facial muscles. Because Botox is a paralytic chemical, it can be fatal in large doses. Botox is generally measured in pharmaceutical units, with 3500 units usually indicated as a lethal dose in humans. The pharmaceutical manufacturer of Botox sells their product to authorized physicians in 100 unit vials.

The most common cosmetic dosage injected is usually less than 100 units, with treatments repeated every few months. Cells, especially muscle cells, have a high turnover rate in the human body and the paralytic effect of the Botox injection is temporary. The usual cosmetic dose of Botox, administered by a physician with specific Botox training, lasts for approximately three months. Most cosmetic surgeons recommend occasional repeat treatments for their patients to maintain firm facial skin with few signs of aging.