In this cross-over design study, the investigators will evaluate whether active muscle contraction following Botox® injection of the forehead/glabellar rhytid complex will impact the onset of action, efficacy, and duration of Botox® treatment.
This cross-over design study will evaluate the onset of action, efficacy, and duration of botulinum toxin A treatment on forehead/glabellar rhytid complexes with and without subsequent muscle contraction.