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 .
The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men.
BACKGROUND Athletes often take and rogenic steroids in an attempt to increase their strength . The efficacy of these substances for this purpose is unsubstantiated , however . METHODS We r and omly assigned 43 normal men to one of four groups : placebo with no exercise ; testosterone with no exercise ; placebo plus exercise ; and testosterone plus exercise . The men received injections of 600 mg of testosterone enanthate or placebo weekly for 10 weeks . The men in the exercise groups performed st and ardized weight-lifting exercises three times weekly . Before and after the treatment period , fat-free mass was determined by underwater weighing , muscle size was measured by magnetic resonance imaging , and the strength of the arms and legs was assessed by bench-press and squatting exercises , respectively . RESULTS Among the men in the no-exercise groups , those given testosterone had greater increases than those given placebo in muscle size in their arms ( mean [ + /-SE ] change in triceps area , 424 + /- 104 vs. -81 + /- 109 square millimeters ; P < 0.05 ) and legs ( change in quadriceps area , 607 + /- 123 vs. -131 + /- 111 square millimeters ; P < 0.05 ) and greater increases in strength in the bench-press ( 9 + /- 4 vs. -1 + /- 1 kg , P < 0.05 ) and squatting exercises ( 16 + /- 4 vs. 3 + /- 1 kg , P < 0.05 ) . The men assigned to testosterone and exercise had greater increases in fat-free mass ( 6.1 + /- 0.6 kg ) and muscle size ( triceps area , 501 + /- 104 square millimeters ; quadriceps area , 1174 + /- 91 square millimeters ) than those assigned to either no-exercise group , and greater increases in muscle strength ( bench-press strength , 22 + /- 2 kg ; squatting-exercise capacity , 38 + /- 4 kg ) than either no-exercise group . Neither mood nor behavior was altered in any group . CONCLUSIONS Supraphysiologic doses of testosterone , especially when combined with strength training , increase fat-free mass and muscle size and strength in normal 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 .