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 .
Recombinant human chorionic gonadotropin but not dihydrotestosterone alone stimulates osteoblastic collagen synthesis in older men with partial age-related androgen deficiency.
Several r and omized trials of and rogen supplementation in older men have been undertaken . However , the relative contributions of testosterone ( T ) and estrogens on bone metabolism in aging men are controversial . Within the setting of two double-blind , placebo-controlled studies , we evaluated the effect of dihydrotestosterone ( DHT ) and recombinant human chorionic gonadotropin ( rhCG ) on bone turnover in healthy , community-dwelling older men with partial and rogen deficiency ( total T < or = 15 nmol/liter ) . In the first study , 35 men ( age 68.3 + /- 6.8 yr ; baseline T , 13.9 + /- 3.3 nmol/liter ) were r and omized to receive either daily transdermal DHT ( n = 17 ) or placebo for 3 months . In the second study , 40 men ( age 67.4 + /- 5.4 yr ; baseline T , 11.4 + /- 2.2 nmol/liter ) were r and omized to receive either rhCG s.c . ( n = 20 ) , two injections weekly , or placebo for 3 months . The following parameters were measured before , monthly during , and 1 month after treatment : serum T , estradiol ( E2 ) , and LH ; markers of bone formation , serum amino-terminal propeptide of type I procollagen ( S-PINP ) and osteocalcin ; markers of bone resorption , serum carboxyterminal cross-linked telopeptide of type I collagen and urinary deoxypyridinoline . Compared with placebo , treatment with DHT significantly increased serum DHT and suppressed LH and T levels , whereas E2 concentrations and markers of bone turnover did not change . In contrast , rhCG therapy significantly increased both T and E2 , with the increases in E2 being supraphysiological . At the same time , rhCG significantly increased S-PINP concentrations with peak levels after 1 month ( Delta40 % ; P = 0.02 compared with placebo ) . In contrast , serum osteocalcin and carboxyterminal cross-linked telopeptide of type I collagen and urinary deoxypyridinoline levels did not change . The change in S-PINP levels correlated with the change in E2 levels ( r = 0.59 ; P = 0.02 ) but not with a change in T. We conclude that in older men with partial age-related and rogen deficiency , rhCG treatment stimulates osteoblastic collagen formation proportionally to increased E2 concentrations but does not alter markers of mature osteoblastic function or bone resorption . In contrast , treatment with a pure , nonaromatizable and rogen ( DHT ) has no effect on bone turnover despite a 20-fold increase in serum levels . Bone resorption was not accelerated during unchanged ( DHT ) or increased ( rhCG ) E2 levels , suggesting that minimal E2 levels are needed to maintain stable resorption , although direct and rogen receptor-mediated effects can not be excluded . If and rogen supplementation is required for aging men , aromatizable and rogens with sufficient endogenous estrogenic activity may have the most beneficial effects on bone
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 .