Results: The T2D-with-insulin group exhibited a significant decrease in plasma adipsin concentration (3.91 ± 1.51 μg/mL) compared to the T2D-w/o-insulin group (5.11 ± 1.53 μg/mL; p < 0.001), whereas the T2D-w/o-insulin group showed a significantly increased plasma adipsin concentration compared to the normoglycemia group (4.53 ± 1.15 μg/mL). Here, INS is linked to type 2 diabetes mellitus.