A multicenter, double-blind, randomized, placebo-controlled study of the efficacy and safety of botulinum toxin type A in the treatment of glabellar lines.

Background: Botulinum toxin type A (BTX-A) is widely used for facial esthetics but is incompletely studied.

Objective: This study was conducted to evaluate the efficacy and safety of BTX-A treatment of glabellar lines.

Methods: Patients with moderate to severe glabellar lines at maximum frown received intramuscular injections of 20 U BTX-A (BOTOX, Allergan, Inc, Irvine, Calif) or placebo into 5 glabellar sites.