Testosterone therapy did not improve insulin resistance ( mean adjusted difference [ MAD ] for HOMA-IR compared with placebo -0.08 [ 95 % CI -0.31 to 0.47 ; P = 0.23 ] ) or glycemic control ( MAD HbA1c 0.36 % [ 0.0-0 .7 ] ; P = 0.05 ) , despite a decrease in fat mass ( MAD -2.38 kg [ -3.10 to -1.66 ] ; P < 0.001 ) and an increase in lean mass ( MAD 2.08 kg [ 1.52-2 .64 ] ; P < 0.001 ) .