Effect of botulinum toxin concentration on reduction in sweating: a randomized, double-blind study.

Dose-response studies of botulinum toxin for reduction of sweating are sparse in the literature. The aim of this study was to determine the most appropriate concentrations of Botox®, Dysport®, Xeomin® and NeuroBloc®, respectively, in order to achieve the greatest reduction in sweating, thus reducing the costs and increasing the safety of treatment. Four concentrations of each product were investigated. Intradermal injections of all products and concentrations were applied to the backs of 20 consenting subjects, in a randomized, double-blind manner. Areas of anhidrotic and hypohidrotic skin were measured with an iodine-starch test after 4, 8 and 12 weeks, respectively. Optimal concentrations were found to be 25 U/ml for Botox and Xeomin, approximately 100 U/ml for Dysport, and 50 U/ml for NeuroBloc. When comparing the mean anhidrotic area per unit for 100 U/ml of each product, the calculated dose conversion ratios were 1:1.6:1.2:1.3 (Botox:Dysport:Xeomin:NeuroBloc). If, instead, the optimal concentration for each product was compared, the dose conversion ratios were 1:4.8:1.3:2.2. Thus, it is crucial to consider botulinum toxin concentration in a treatment regimen.