We cannot confirm a significant association between elevated GGT and HbA1C levels. As GGT is a marker that takes a long time to climb, there was no positive correlation between GGT and FBS, which is related to the length of time patients have diabetes. Although the association of the underlying pathophysiological mechanism between GGT and T2DM has not been precisely elucidated, insulin resistance, oxidative stress, and systemic inflammation appear to be involved. Accordingly, it is proposed that evaluation of additional inflammatory markers such as C-reactive protein by a certified extreme-sensitivity assay is additional in an attempt to confirm this theory. The results of our study on patients were in contrast to studies that showed that GGT levels were significantly higher in all diabetic patients who were not in the healthy control group. In stark contrast, other studies have shown that GGT levels increase only in diabetic patients with chronic diabetic complications such as retinopathy and neuropathy, which may have been due to oxidative stress and the role of GGT in diabetes. Further studies are needed to investigate the Biological underlying mechanism of GGT increase in T2DM patients.