Figure 2.

Botulinum toxin injection scheme. Most trials of BoNT for the treatment of depression used 29 units of onabotulinumtoxinA distributed to five injection points (7 U procerus muscle; 6 U corrugator muscle, medially, bilaterally; 5 U corrugator muscle, laterally, bilaterally) for women. Men received two more units at each injection point on account of their usually higher muscle mass. In clinical practice, additional injections may be placed in the chin area to preclude a mouth frown (2-3 U depressor anguli oris muscle, bilaterally; 3-5 U mentalis muscle, bilaterally).