Effects of metformin and short-term lifestyle modification on the improvement of male hypogonadism associated with metabolic syndrome

Aim. The metabolic syndrome is associated with male hypogonadism, but specific studies about the mechanisms and treatment of the testosterone deficit are scanty. The aim of this study was to evaluate the effects of metformin combined with diet and physical activity on the testicular function of men with metabolic syndrome. Methods. Thirty-five men (40.4 +/- 13.3 years old) with metabolic syndrome were evaluated before and after a four-month period of therapy with metformin 850 mg twice daily, associated with a balanced normocaloric diet and subtle improvement in physical activity. The subjects were divided in two groups: 21 males with normal plasma testosterone levels WOO ng/dL) and 14 males with low plasma testosterone levels (<300 ng/dL). Results. There was a significant decrease in fasting insulin levels and HOMA-IR after treatment (P=0.01 and P=0.06), which was more pronounced in the hypogonadic group (for the effect of absence or presence of hypogonadism, P=0.04). The mean total and free testosterone levels increased significantly after treatment in both groups, similarly. The increase in FSH levels was more pronounced in the hypogonadic group than in the eugonadic group. Conclusion. In this series of males with metabolic syndrome, treatment with metformin associated with healthy dietary modifications and a mild physical activity increment resulted in significant improvement of insulin sensitivity and increase in total and free testosterone levels, regardless of the presence of hypogonadism.