TNF and metabolic syndrome: The pooled findings using random-effects model showed that berberine use in patients with MetS and related disorders significantly decreased the concentration level of CRP (SMD = − 1.54; 95% CI − 1.86, − 1.22; p < 0.05), TNF-α (SMD = − 1.02; 95% CI − 1.27, − 0.77; p < 0.05), and IL-6 (SMD = − 1.17; 95% CI − 1.53, − 0.81; p < 0.05).