Methylglyoxal (MGO), a glycolysis by-product and precursor to advanced glycation endproducts (AGEs), is associated with glucose intolerance, type 2 diabetes, and vascular dysfunction. This study examined the long-term effects of elevated MGO on blood pressure, insulin sensitivity, and vascular function in healthy mice. Male C57Bl/6J mice were assigned to control (n = 16) or MGO-treated groups (50 mM in drinking water for 13 weeks, n = 16). Measurements included body weight, fasting plasma glucose, water consumption, blood pressure, and analysis of plasma/tissue for MGO, AGEs, glyoxalase activity, and inflammation markers. Endothelial function was assessed using wire myography, and the response of human placental arteries to MGO-modified insulin was evaluated. MGO treatment significantly increased plasma MGO (123.3%, p <
0.001), AGEs MG-H1 (208.6%, p <
0.001) and CEL (64.3%, p <
0.001), and AGEs in the heart, kidney, and liver, along with body weight (+ 6.4%, p = 0.032) and blood pressure (systolic + 5.0%, p = 0.046
diastolic + 6.5%, p = 0.043). Glucose sensitivity and endothelial function remained unaffected. CRP levels rose, and MGO-modified insulin enhanced vascular contraction. In conclusion, chronic MGO exposure increased plasma MGO to diabetic-like levels, raised body weight and blood pressure, and did not alter glucose sensitivity or endothelial function. Modification of insulin by MGO may contribute to MGO-related changes in blood pressure.