Conclusions Oral TRT produces significant CV risk .
Differences in the degree to which serum DHT is elevated may underlie the varying CV risk by TRT administration route , as elevated serum dihydrotestosterone has been shown to be associated with CV risk in observational studies
Background Potential cardiovascular ( CV ) risks of testosterone replacement therapy ( TRT ) are currently a topic of intense interest .
However , no studies have addressed CV risk as a function of the route of administration of TRT .
A randomized pilot study of monthly cycled testosterone replacement or continuous testosterone replacement versus placebo in older men.
CONTEXT Cycling and rogens has been reported by athletes to improve physical performance by enhancing muscle mass and strength , a paradigm that has not been studied , and may have clinical value in older men being treated with testosterone .  OBJECTIVE We investigated the efficacy of a monthly cycled testosterone regimen that uses half the testosterone dose as the current st and ard of care continuous therapy on body composition and muscle strength in older men . DESIGN , SETTING , AND PATIENTS Twenty-four community-dwelling older men 70 ± 2 yr of age with total testosterone levels below 500 ng/dl were r and omized at the Institute for Translational Sciences- Clinical Research Center into a 5-month double-blind placebo-controlled trial . INTERVENTION Subjects were dosed weekly for 5 months , receiving continuous testosterone ( TE , n = 8 ; 100 mg testosterone enanthate , i m injection ) , monthly cycled testosterone ( MO , n = 8 ; alternating months of testosterone and placebo ) , or placebo ( PL , n = 8) . MAIN OUTCOME MEASURES Main outcomes included body composition by dual-energy x-ray absorptiometry and upper and lower body muscle strength . Secondary outcomes included body weight , serum hormones , and mixed-muscle protein fractional synthesis rate ( FSR ) . RESULTS Total lean body mass was increased and percent fat was reduced after 5 months in TE and MO ( P < 0.05 ) . Upper body muscle strength increased in TE , and lower body muscle strength increased in TE and MO ( P < 0.05 ) . FSR increased in TE and MO ( P < 0.05 ) but not in PL . CONCLUSIONS Cycled testosterone  improved body composition and increased muscle strength compared with placebo and increased FSR similarly to continuous testosterone
Conclusions Oral TRT produces significant CV risk .
Differences in the degree to which serum DHT is elevated may underlie the varying CV risk by TRT administration route , as elevated serum dihydrotestosterone has been shown to be associated with CV risk in observational studies
Background Potential cardiovascular ( CV ) risks of testosterone replacement therapy ( TRT ) are currently a topic of intense interest .
However , no studies have addressed CV risk as a function of the route of administration of TRT .