Supplementary Figure 3C showed an excellent homogeneity in each group (I2 = 0%, p = 0.53). Therefore, a fixed effect model was adopted. Meta-analysis showed that using probiotics had a considerably lower Insulin level than the control group {SMD = -0.48, 95% CI (-0.74, -0.22), p = 0.0003}. In subgroup analysis (Supplementary Figure 4C), patients with T2DM taking probiotics lasted for six to eight weeks, and 12 to 24 weeks had a substantially lower Insulin level than the control group {SMD = -0.44, 95%CI(-0.79, -0.09), p = 0.01}, {SMD = -0.53, 95%CI(-0.93, 0.13), p = 0.009}, respectively. Here, INS is linked to type 2 diabetes mellitus.