In one study, J. Kaufman-Janette et al (2021) looked at higher doses of botulinum toxin A for injections into the glabellar folds. This involved 5 studies that were randomized, double-blinded, and with varying population sizes.
Botulinum toxin formulations approved for the treatment of glabellar wrinkles in the USA or in Europe (Abotulinumtoxin A, Incobotulinumtoxin A, Onabotulinumtoxin A) were used. A high dosage was defined as a dosage that was higher than the dosage indicated in the technical information of the respective formulations.