Doses of 20 to 40 U BTX-A produced dramatic changes in eyebrow position that may be due to diffusion of BTX-A into and partial inactivation of the medial fibers of the frontalis, with resulting increased muscle tone in the lateral and superior muscle fibers of the frontalis.
No takes yet. Share an insight, caveat, or question.
Carruthers et al. (2007) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: