Optimal Dosage of Botulinum Toxin Type A for Treatment of Glabellar Frown Lines: Efficacy and Safety in a Clinical Trial

BACKGROUND Various preparations of botulinum toxin type A (BTX-A) are used to reduces glabellar (frown) lines. However, dose-related safety and efficacy of intramuscular injections of a widely used, locally produced BTX-A in China has not been established. OBJECTIVE Assessment of dose-dependent safety and efficacy of Chinese botulinum toxin type A (Hengli BTX-A [HBTX-A]) intramuscular injections on glabellar lines. METHODS Four hundred eighty-eight BTX-A-naive participants were included in the double-blind trial and randomly divided into placebo (n = 122), low-dose (n = 183), and high-dose (n = 183) treatment groups for injection with saline solution, 10 units and 20 units of HBTX-A, respectively, at 4 sites in the corrugator muscle and 1 site in the procerus muscle. Outcomes were recorded before treatment and after 7, 30, 60, and 120 days, including glabellar line severity at maximum contraction and relaxation. RESULTS Significantly greater improvement was observed in both HBTX-A groups in comparison with the placebo group (p <.05). Better efficacy was obtained in the high-dose treatment group. More participants developed adverse events after treatment with HBTX-A doses, than with the placebo (p <.05). CONCLUSION Twenty-unit HBTX-A provided optimal improvement in glabellar lines, and its use might minimize injection frequency while maintaining acceptable safety.