Metformin is commonly prescribed as first-line therapy for type 2 diabetes mellitus. Despite its clinical benefit. long-term use has been associated with vitamin B-12 deficiency, which can lead to neurological dysfunction and cognitive disorders, including Alzheimer’s disease. Awareness of this drug-nutrient interaction among healthcare professionals is essential for safe and effective diabetes management. This study evaluated and compared the knowledge of metformin-related vitamin B-12 deficiency and its neurological implications among medical and pharmacy graduates in Libya. A cross-sectional survey was conducted from February to May 2024 among 100 recent graduates (50 medical and 50 pharmacy). The self-designed questionnaire assessed 27 questions that structured knowledge of diabetes pathophysiology, metformin pharmacotherapy, mechanisms of vitamin B-12 deficiency, and its potential association with Alzheimer’s disease. Comparisons were performed using the Chi-square test. Pharmacy graduates demonstrated higher overall knowledge of diabetes management compared with medical graduates (77.2% vs. 66.4%; OR=1.72; p<0.001) and significantly greater awareness of metformin-related complications, particularly vitamin B-12 deficiency. Knowledge regarding metformin-vitamin B-12 interactions and Alzheimer’s disease was comparable between groups. Although most participants recognized dietary sources and monitoring recommendations, inconsistencies were observed in clinical application. Pharmacy graduates demonstrated superior awareness of metformin safety; nevertheless, enduring deficiencies in knowledge across medical and pharmacy graduates indicate a critical need for integrated interprofessional education to advance preventive care and risk mitigation in type 2 diabetes mellitus.