Association Between Serum Magnesium Levels And Glycemic Control (Hba1c) In Obese Patients With Type 2 Diabetes Mellitus: A Narrative Review

Abstract

Magnesium acts as a cofactor for glucose transport, insulin signaling, and inflammatory pathways. Hypomagnesemia is commonly identified in individuals with type 2 diabetes mellitus (T2DM). We performed a narrative review to evaluate literature published between 2019 and 2025 examining associations between serum magnesium and measures of glycemic control (HbA1c), as well as oral magnesium supplementation interventions in obese adults with T2DM. Observational studies (predominantly cross-sectional and real-world data) demonstrate low serum magnesium to be associated with elevated HbA1c across heterogeneous cohorts, though studies vary in definitions of hypomagnesemia, measures of adiposity used, and covariates adjusted for (Kocyigit et al., 2023; Erinc et al., 2025). Analyses restricted to patients with obesity further demonstrate associations between obesity and abdominal obesity with low serum magnesium in individuals with T2DM; this may identify a susceptibility phenotype in which adiposity-driven insulin resistance contributes to magnesium dysregulation and poor glycemic control (Xu et al., 2024). Determinant analyses have also described both obesity and poor glycemic control as common correlates of hypomagnesemia in those with T2DM (Abdullah et al., 2025). Interventional evidence assessing the impact of oral magnesium supplementation on glycemic indices in T2DM from meta-analyses suggest improvements in glycemic parameters (including HbA1c), however, few studies are stratified by obesity status and there is high heterogeneity between trials (Asbaghi et al., 2022; Xu et al., 2023). In summary, recent literature continues to find an inverse association between serum magnesium and HbA1c in T2DM. There remains a need for obesity-stratified longitudinal studies and pragmatic trials adjusting for renal function, medications, and dietary intake.