3Rs Webinar on Botulinum Neurotoxin Testing

As part of the 3Rs Training Webinar Series led by Dr. Kathrin Herrmann, Director of the Education Program at the Center for Alternatives to Animal Testing (CAAT), Justine C. Watkins from Utrecht University’s Faculty of Veterinary Medicine will present her team’s latest research on replacing animal use in botulinum neurotoxin (BoNT) testing.

BoNT products, widely known under the trade name “Botox,” must undergo rigorous batch potency testing to ensure safety and efficacy. For decades, the regulatory gold standard has been the mouse lethality bioassay (LD50)—a severe procedure causing significant animal suffering, with questionable reproducibility and limited relevance to human biology. Watkins will share findings from her 2025 NAM Journal paper, which charts the transition toward non-animal new approach methodologies (NAMs), particularly cell-based assays (CBAs), in Europe. Drawing on analyses of Non-Technical Summaries from facilities in the UK, Germany, and Ireland, she will explain why LD50 testing persists despite available alternatives, outline regulatory and technical barriers to full replacement, and call for greater transparency in reporting animal use. The session will conclude with concrete recommendations to accelerate the adoption of scientifically robust, humane potency testing methods worldwide.