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.