Background: Botulinum neurotoxin A (BoNT-A) injection is the most widely performed aesthetic procedure and a first-line therapeutic option for various medical conditions. The potential for BoNT-A immunoresistance and secondary nonresponse related to neutralizing antibody (NAb) formation warrants attention as the range of BoNT-A aesthetic applications continues to expand. Methods: An international multidisciplinary panel reviewed published evidence on BoNT-A immunoresistance in aesthetic and therapeutic applications and discussed best practices integrating clinical, ethical, and aesthetic considerations. Consensus statements relating to awareness, assessment, and management of the risk of NAb-related secondary nonresponse in aesthetic practice were developed. Results: There was a consensus that, as doses used in aesthetic practice become like those in therapeutics, rates of NAb formation may be expected to increase. However, the true extent of NAb formation in aesthetics is likely underestimated due to limitations of published evidence and variability in treatment patterns of aesthetic patients. Since BoNT-A therapy is often lifelong, practitioners need to recognize immunogenicity as a potential complication that might affect future therapeutic use and strive to minimize modifiable risk factors. The selection and use of a BoNT-A product with the least immunogenic potential from the beginning may thus be advantageous, especially when treatment with high doses is planned. Conclusions: In view of current trends in BoNT-A aesthetic use, it is essential for practitioners to conduct thorough clinical assessments, inform patients of treatment risks, and develop BoNT-A treatment plans to minimize immunogenicity. This can help preserve the option of continued or future BoNT-A treatment with satisfactory outcomes.

RESULTS Most (76.5%) patients were women. The mean age of the patients was 46.9 ± 10.0 years. Mean severities (on the Merz scale) for at-rest and dynamic (with expression) GFLs at baseline were 1.3 ± 1.10 and 3.4 ± 0.38, respectively, and decreased on Day 14 (p < 0.05). Treatment response rates (> 1-point improvement) for at-rest and dynamic (with expression) GFLs on Day 4 were 40% and 100%, respectively. All patients reported being satisfied or very satisfied, and 64.3%-71.4% indicated that their facial wrinkles had improved on Day 2.CONCLUSION IncobotulinumtoxinA was fast acting with visible improvements by Day 4 and all patients expressed satisfaction with their treatment after two days. GFLs saw the most improvement among the facial characteristics measured.