The present analysis provides an estimate of the average treatment effects of testosterone therapy in middle-aged men .
OBJECTIVES Ageing in men is associated with a gradual decline in serum testosterone levels and a concomitant loss of muscle mass , accumulation of central adiposity , impaired mobility and increased risk of bone fractures .
Whether and rogen treatment might be beneficial in these subjects is still under debate .
We have carried out a systematic review of r and omized controlled trials ( RCTs ) evaluating the effects of testosterone ( T ) administration  to middle-aged and ageing men on body composition , muscle strength , bone density , markers of bone metabolism and serum lipid profile .
Exogenous testosterone (T) alone or with finasteride increases physical performance, grip strength, and lean body mass in older men with low serum T.
Testosterone ( T ) therapy in older men with low serum T levels increases lean body mass and decreases fat mass . These changes might improve physical performance and strength ; however , it has not been established whether T therapy improves functional outcome in older men . Moreover , concerns exist about the impact of T therapy on the prostate in older men . The administration of finasteride ( F ) , which partially blocks the conversion of T to the more potent and rogen , dihydrotestosterone , attenuates the impact of T replacement on prostate size and prostate-specific antigen . We hypothesized that T replacement in older , hypogonadal men would improve physical function and that the addition of F to this regimen would continue to provide the T-induced improvements in physical performance , strength , and body composition . Seventy men with low serum T ( < 350 ng/dl ) , age 65 yr and older , were r and omly assigned to receive one of three regimens for 36 months : 1 ) T enanthate , 200 mg i m every 2 wk , with placebo pills daily ( T-only ) ; 2 ) T enanthate , 200 mg every 2 wk , with 5 mg F daily ( T + F ) ; or 3 ) placebo injections and pills ( placebo ) . We obtained serial measurements of timed physical performance , grip strength , lower extremity strength , body composition ( by dual-energy x-ray absorptiometry ) , fasting cholesterol profiles , and hormones .  Fifty men completed the 36-month protocol . After 36 months , T therapy significantly improved performance in a timed functional test when compared with baseline and placebo [ 4.3 + /- 1.6 % ( mean + /- sem , T-only ) and 3.8 + /- 1.0 % ( T + F ) vs. -5.6 + /- 1.9 % for placebo ( P < 0.002 for both T and T + F vs. placebo ) ] and increased h and grip strength compared with baseline and placebo ( P < 0.05 ) . T therapy increased lean body mass [ 3.77 + /- 0.55 kg ( T-only ) and 3.64 + /- 0.56 kg ( T + F ) vs. -0.21 + /- 0.55 kg for placebo ( P < 0.0001 ) ] , decreased fat mass , and significantly decreased total cholesterol , low-density lipoprotein , and leptin , without affecting high-density lipoprotein , adiponectin , or fasting insulin levels . These results demonstrate that T therapy in older men with low serum T improves physical performance and strength over 36 months , when administered alone or when combined with F , and suggest that high serum levels of dihydrotestosterone are not essential for these beneficial effects of T in men
The present analysis provides an estimate of the average treatment effects of testosterone therapy in middle-aged men .
OBJECTIVES Ageing in men is associated with a gradual decline in serum testosterone levels and a concomitant loss of muscle mass , accumulation of central adiposity , impaired mobility and increased risk of bone fractures .
Whether and rogen treatment might be beneficial in these subjects is still under debate .
We have carried out a systematic review of r and omized controlled trials ( RCTs ) evaluating the effects of testosterone ( T ) administration  to middle-aged and ageing men on body composition , muscle strength , bone density , markers of bone metabolism and serum lipid profile .