GCG and type 2 diabetes mellitus: In a retrospective one-year cohort study involving male outpatients with T2D, Lisco et al. found that the combination of GLP-1 RAs with metformin, compared with metformin monotherapy, produced marked increases in TT (+41.41 ± 6.11 ng/dL, p < 0.0001) and free testosterone (fT) (+0.44 ± 0.09 ng/dL, p < 0.0001) levels.