GLP-1 receptor agonists used before bariatric surgery show no negative impact on postoperative weight loss outcomes, contradicting earlier single-center studies. Among 2,379 patients across Indiana health systems, those using GLP-1 medications preoperatively achieved similar weight loss trajectories through 12 months post-surgery, with 20.7% total weight loss versus 22.0% in non-users. The finding held even in a diabetes subgroup analysis comparing GLP-1 users to those on other diabetes medications. This represents a significant departure from previous research suggesting preoperative GLP-1 use might blunt surgical weight loss benefits. The implications are substantial for clinical practice, as millions now use GLP-1 medications like semaglutide and tirzepatide for weight management. Previously, some surgeons recommended discontinuing these drugs before bariatric procedures, fearing reduced efficacy. This multi-system analysis provides reassurance that patients don't need to choose between medical and surgical weight loss interventions. However, the 8.1% prevalence of preoperative GLP-1 use reflects the study period (2020-2024) when these medications were less widely prescribed. As GLP-1 adoption accelerates, larger datasets will be needed to confirm these findings across diverse populations and longer follow-up periods.