title: A randomized pilot study of monthly cycled testosterone replacement or continuous testosterone replacement versus placebo in older men.
abstract: BACKGROUND
  Cycling androgens 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 standard of care continuous therapy on body composition and muscle strength in older men.
  
  
  METHODS
  Twenty-four community-dwelling older men 70 ± 2 yr of age with total testosterone levels below 500 ng/dl were randomized at the Institute for Translational Sciences-Clinical Research Center into a 5-month double-blind placebo-controlled trial.
  
  
  METHODS
  Subjects were dosed weekly for 5 months, receiving continuous testosterone (TE, n = 8; 100 mg testosterone enanthate, im injection), monthly cycled testosterone (MO, n = 8; alternating months of testosterone and placebo), or placebo (PL, n = 8).
  
  
  METHODS
  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.
authors.affiliation: Department of Internal Medicine, The University of Texas Medical Branch at Galveston, Texas 77555, USA.
authors.forename: Melinda
authors.initials: M
authors.lastname: Sheffield-Moore
authors.forename: E Lichar
authors.initials: EL
authors.lastname: Dillon
authors.forename: Shanon L
authors.initials: SL
authors.lastname: Casperson
authors.forename: Charles R
authors.initials: CR
authors.lastname: Gilkison
authors.forename: Douglas
authors.initials: D
authors.lastname: Paddon-Jones
authors.forename: William J
authors.initials: WJ
authors.lastname: Durham
authors.forename: James J
authors.initials: JJ
authors.lastname: Grady
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Urban
mesh_terms: D000368:Aged; D000728:Androgens / Q000008:administration & dosage*; D001823:Body Composition / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D004334:Drug Administration Schedule; D020249:Hormone Replacement Therapy / Q000379:methods*; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects; D010865:Pilot Projects; D013739:Testosterone / Q000008:administration & dosage* / Q000097:blood; D016896:Treatment Outcome
chemical_list: D000728:Androgens; D013739:Testosterone