title: Onset of effects of testosterone treatment and time span until maximum effects are achieved.
abstract: OBJECTIVE
  Testosterone has a spectrum of effects on the male organism. This review attempts to determine, from published studies, the time-course of the effects induced by testosterone replacement therapy from their first manifestation until maximum effects are attained.
  
  
  METHODS
  Literature data on testosterone replacement.
  
  
  RESULTS
  Effects on sexual interest appear after 3 weeks plateauing at 6 weeks, with no further increments expected beyond. Changes in erections/ejaculations may require up to 6 months. Effects on quality of life manifest within 3-4 weeks, but maximum benefits take longer. Effects on depressive mood become detectable after 3-6 weeks with a maximum after 18-30 weeks. Effects on erythropoiesis are evident at 3 months, peaking at 9-12 months. Prostate-specific antigen and volume rise, marginally, plateauing at 12 months; further increase should be related to aging rather than therapy. Effects on lipids appear after 4 weeks, maximal after 6-12 months. Insulin sensitivity may improve within few days, but effects on glycemic control become evident only after 3-12 months. Changes in fat mass, lean body mass, and muscle strength occur within 12-16 weeks, stabilize at 6-12 months, but can marginally continue over years. Effects on inflammation occur within 3-12 weeks. Effects on bone are detectable already after 6 months while continuing at least for 3 years.
  
  
  CONCLUSIONS
  The time-course of the spectrum of effects of testosterone shows considerable variation, probably related to pharmacodynamics of the testosterone preparation. Genomic and non-genomic effects, androgen receptor polymorphism and intracellular steroid metabolism further contribute to such diversity.
authors.affiliation: Scientific Affairs Men's Healthcare, BU General Medicine/Men's Healthcare, Bayer Pharma AG, D-13342 Berlin, Germany. farid.saad@bayer.com
authors.forename: Farid
authors.initials: F
authors.lastname: Saad
authors.forename: Antonio
authors.initials: A
authors.lastname: Aversa
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Isidori
authors.forename: Livia
authors.initials: L
authors.lastname: Zafalon
authors.forename: Michael
authors.initials: M
authors.lastname: Zitzmann
authors.forename: Louis
authors.initials: L
authors.lastname: Gooren
mesh_terms: D000818:Animals; D020249:Hormone Replacement Therapy / Q000379:methods*; D006801:Humans; D008297:Male; D013739:Testosterone / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D013739:Testosterone