By contrast, a double-blind crossover trial in 14 insulin-treated patients with type 2 diabetes and low serum magnesium found that 6 weeks of oral magnesium supplementation (15 mmol/day) increased serum magnesium but did not improve insulin sensitivity, HbA1c, or insulin requirements, apart from a small reduction in high-density lipoprotein (HDL) cholesterol [50]. Here, INS is linked to type 2 diabetes mellitus.