Garry R. Lee, MD, is an Allergan Medical Institute Botox/Juvederm Physician Instructor for the State of Nevada--one of only 3 teachers selected from 700 Clinics @Las Vegas.
Botox Cosmetic comes in 50 Unit vials which must be mixed with normal saline to be able to inject Botox into your wrinkles. The amount of normal saline, or water, is variable by the preference of your Botox injector and I have seen it range from the Botox standard of 1.25 cc of saline per 50 Unit bottle to 4.0 cc of saline. The problem is too much saline will cause it to dilute and to migrate into areas you don’t want to treat and can cause muscles to relax--which you don’t want to relax. Dr. Lee uses 0.625 cc of saline—half the amount of most—to inject his patients to prevent accidental spread to unintended areas, though it requires more precision in his placement.
Typically most patients will need 50 Units of Botox with most needing 20 Units between the eyes—the Glabella area, known as the “elevens,” 18 Units in the forehead, and 12 Units in the Crow’s Feet at the sides of your eyes. However there is much variation due to variation in anatomy with more Botox needed in larger muscles and less in smaller muscles. Men tend to need more Botox than women due to larger muscle size. The way to think about it is that the concentration of Botox must be the same to be effective and a muscle twice as large, will naturally need more Botox.
Botox is typically used in the upper face and Crow’s Feet area because the wrinkles here are primarily due to overuse of these muscles, causing them to enlarge or hypertrophy, which accentuates the wrinkles between them.
Consequently, since Botox works by relaxing these muscles, they can no longer flex on either side of each wrinkle minimizing visibility and movement. These are called dynamic wrinkles, since they are most apparent with movement of these muscles. On the other hand, static wrinkles are present in these areas when the loose skin is apparent even without any movement of these wrinkles. Hence, these static wrinkles cannot be treated with Botox since they are already apparent as loose skin when no movement is even attempted. Static wrinkles can be treated with Juvederm, the hyaluronic acid wrinkle filler from Allergan designed to lift loose skin.