Testosterone supplementation did not show consistent benefit for cardiovascular risk , sexual function , mood and behavior , or cognition .
Studies that examined clinical cardiovascular endpoints have not favored testosterone therapy over placebo .
Testosterone is ineffective in treating erectile dysfunction and controlled trials did not show a consistent effect on libido .
Testosterone supplementation consistently increased muscle strength but did not have beneficial effects on physical function .
Most studies on mood-related endpoints found no beneficial effect of testosterone treatment on personality , psychological well-being , or mood .
Testosterone products are recommended by some prescribers in response to a diagnosis or presumption of " low testosterone " ( low-T ) for cardiovascular health , sexual function , muscle weakness or wasting , mood and behavior , and cognition .
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
Testosterone supplementation did not show consistent benefit for cardiovascular risk , sexual function , mood and behavior , or cognition .
Studies that examined clinical cardiovascular endpoints have not favored testosterone therapy over placebo .
Testosterone is ineffective in treating erectile dysfunction and controlled trials did not show a consistent effect on libido .
Testosterone supplementation consistently increased muscle strength but did not have beneficial effects on physical function .
Most studies on mood-related endpoints found no beneficial effect of testosterone treatment on personality , psychological well-being , or mood .
Testosterone products are recommended by some prescribers in response to a diagnosis or presumption of " low testosterone " ( low-T ) for cardiovascular health , sexual function , muscle weakness or wasting , mood and behavior , and cognition .