The following variables were associated with metformin in NAFLD patients: decreased of alanine aminotransferase (ALT) level (mean difference [MD] = −10.84, 95% confidence interval [CI] = −21.85 to 0.16, P = .05); decreased of aspartate amino transferase (AST) level (MD = −4.82, 95% CI = −9.33 to −0.30, P = .04); decreased of triglyceride (TG) level (MD = −0.17, 95% CI = −0.26 to −0.08, P = .0002); decreased of total cholesterol (TC) level (MD = −0.29, 95% CI = −0.47 to −0.10, P = .003); decreased of insulin resistance (IR) level (MD = −0.42, 95% CI = −0.82 to −0.02, P = .04). The gene discussed is GPT; the disease is metabolic dysfunction-associated steatotic liver disease.