Dr. Timothy Corcoran Flynn of the University of North Carolina, Chapel Hill, said there has been a growing interest in cosmetic procedures among men, but most practices see a majority of women patients.
The study, published in the journal Dermatologic Therapy, found men often require more units of Botox than women -- possibly because men have a greater muscle mass than women. Similarly, it has been a common clinical observation that larger, stronger men need more units per treatment area than slender, small-boned men.
"Various areas of the male face can be treated with Botox, and injections need to keep in mind the greater muscle mass in men," the study said.
The most common cause of inadequate results in male patients is under-dosing, which may lead to men requiring additional Botox injections, Flynn.