However, this inhibitory effect is significantly weakened in patients with T2DM, indicating that its potential application in diabetes treatment requires further investigation.241 Through this series of complex molecular and cellular mechanisms, GLP-1 plays a vital role in the physiological and pathological processes of metabolic diseases like T2DM.232,233,241,259 (Fig. 2). Here, GCG is linked to type 2 diabetes mellitus.