In these studies, testosterone-deficient men, who also had T2DM, when given androgen replacement therapy, showed improvement in glucose homeostasis parameters.4, 5 However, these clinical studies did not show the effect of testosterone supplementation on the insulin responsiveness and gluconeogenesis in the liver, and on the serum levels of known regulators of glucose homeostasis, like insulin, glucagon, leptin, interleukin-6, and so on. This evidence concerns the gene INS and type 2 diabetes mellitus.