Is Cold Storage Still a Must? Evaluating Room-Temperature OnabotulinumtoxinA for Glabellar Lines Treatment

Background: New botulinum toxin type A (BoNT-A) formulations eliminated cold-chain storage before reconstitution. Nonetheless, concerns remain about BoNT-A properties when stored at room temperature after reconstitution. Aim: This study aimed to evaluate the sterility and effectiveness of BoNT-A storage at room temperature in glabellar wrinkles. Methods: BoNT-A (Allergan Botox, Brazil) was reconstituted and maintained in a stove at 37°C for 60 days and then tested for sterility according to the Pharmacopeia guidelines. Then, sixty patients aged 25–60 years were divided into two groups: Group 1 (G1) received BoNT-A immediately after reconstitution, and Group 2 (G2) received BoNT-A after 7 days at room temperature. Participants were assessed for wrinkle severity using the Merz Scale, satisfaction with treatment using the Face-Q scale, and muscle activity by electromyography. Data were collected before injections and after 15, 30, 60, and 90 days. Results: Absence of turbidity evidenced no microbial growth in all periods analyzed. Both groups showed significant reductions in glabellar contraction (p < 0.001), wrinkle severity (p < 0.05), and improved satisfaction. G1 presented lower wrinkle severity, while G2 reported higher satisfaction (p < 0.05). Conclusion: Room temperature and longer storage periods may not affect OnabotulinumtoxinA sterility and clinical results.