A multicenter, randomized, open-label comparative study of prabotulinumtoxinA with two different dosages and diverse proportional injection styles for the reduction of gastrocnemius muscle hypertrophy in Asian women.

A botulinum toxin (BTX) injection can be a simple and safe alternative to calf reduction surgery or liposuction without interrupting daily life. However, its optimum dosage and clinical response are not yet well known. A total of 40 patients with bilateral gastrocnemius muscle hypertrophy were enrolled in this study. All volunteers were randomly categorized into four groups and then administered different amounts of BTX (160 U and 200 U) on the medial and lateral aspects of their calves. All subjects showed clinical improvement with a reduction in the gastrocnemius muscle size after BTX injection. However, our results showed that the decrease in leg circumference was not dose dependent. No side effects of the injections, such as weakness of the legs, deformity, or abnormal sensation, were observed. There were also no cases of swelling, edema, hematoma, or infection. BTX at both dosages can be safely and effectively applied for calf muscle contouring without disturbing gait during walking or running.