['To evaluate the effect of testosterone replacement therapy in patients with hypogonadotrophic hypogonadism (HH) on insulin sensitivity and high sensitivity C reactive protein (hsCRP).', '21 males with HH, aged 15 - 30, and 18 age, and BMI-matched healthy males underwent detection of homeostasis model assessment insulin resistance index (HOMA-IR). Second, the values of weight, abdominal circumstance, grips strength, body composition, total testosterone (TT), fast blood glucose and insulin, serum lipid profile, and hsCRP were compared before and after 9-month testosterone replacement therapy in the HH patient group.', '(1) Before treatment the TT level of the HH patients WAS (0.9 +/- 0.6) nmol/L, significantly lower than that of the healthy control group (18.8 +/- 3.2) nmol/L. The fast insulin level of the HH patients was (16.0 +/- 9.8) mIU/L, significantly higher than that of the control group [(8.4 +/- 3.3) mIU/L, P = 0.018]. The HOMA-IR of the HH patient was 3.7 +/- 2.4, not significantly different from that of the control group (1.8 +/- 0.7, P = 0.021). (2) After testosterone therapy, the fast insulin level of the HH patients decreased from (16.0 +/- 9.8) mIU/L to (12.1 +/- 7.4) mIU/L (P = 0.03); the HOMA-IR decreased from (3.7 +/- 2.4) to (2.7 +/- 1.7) (P = 0.045); and the total cholesterol, LDL-c, HDL-c, and Triglyceride all decreased, but not significantly (all P > 0.05). The hsCRP decreased from (1.49 +/- 1.18) mg/L to (0.70 +/- 0.56) mg/L (P = 0.025).'] Does [ Testosterone replacement in hypogonadotropic hypogonadal young male improve insulin sensitivity ]?