Furthermore, significant changes in the gut microbiota composition were observed in type 2 diabetes patients treated with liraglutide, a GLP-1 receptor agonist.86 In obese mice, long-acting GLP-1 fusion peptide (MGLP_1) reduces the ratio of Firmicutes to Bacteroidetes, increases the abundance of beneficial genera (Bifidobacterium, Lachnospiraceae, and Turicibacter), and decreases the abundance of harmful genera (Clostridium and Romboutsia).6 Here, GCG is linked to type 2 diabetes mellitus.