Vitamin B12 Deficiency in Patients Taking Metformin: Pathogenesis and Recommendations

Metformin is a cornerstone therapy for type 2 diabetes mellitus due to its glucose-lowering efficacy and additional benefits such as reducing cardiovascular mortality. However, accumulating evidence suggests an association between long-term metformin use and vitamin B12 deficiency, which can lead to serious clinical consequences. This review aims to synthesize current knowledge on the pathogenesis, prevalence, clinical implications, and management of metformin-induced vitamin B12 deficiency. Given the significant clinical implications, it is crucial to monitor and manage vitamin B12 levels in patients using metformin. This review emphasizes the importance of early detection and supplementation to prevent adverse outcomes. By analyzing the current evidence, the review aims to inform healthcare professionals about best practices for managing vitamin B12 deficiency in patients on metformin, offering insights to guide future clinical practices and research directions.