Testosterone Treatment and Sexual Function in Older Men With Low Testosterone Levels

J Clin Endocrinol Metab. 2016 Aug;101(8):3096-104. doi: 10.1210/jc.2016-1645. Epub 2016 Jun 29.


Context: The Testosterone Trials are a coordinated set of seven trials to determine the efficacy of T in symptomatic men ≥65 years old with unequivocally low T levels. Initial results of the Sexual Function Trial showed that T improved sexual activity, sexual desire, and erectile function.

Objective: To assess the responsiveness of specific sexual activities to T treatment; to relate hormone changes to changes in sexual function; and to determine predictive baseline characteristics and T threshold for sexual outcomes.

Design: A placebo-controlled trial.

Setting: Twelve academic medical centers in the United States.

Participants: A total of 470 men ≥65 years of age with low libido, average T <275 ng/dL, and a partner willing to have sexual intercourse at least twice a month.

Methods: Men were assigned to take T gel or placebo for 1 year. Sexual function was assessed by three questionnaires every 3 months: the Psychosexual Daily Questionnaire, the Derogatis Interview for Sexual Function, and the International Index of Erectile Function.

Results: Compared with placebo, T administration significantly improved 10 of 12 measures of sexual activity. Incremental increases in total and free T and estradiol levels were associated with improvements in sexual activity and desire, but not erectile function. No threshold T level was observed for any outcome, and none of the 27 baseline characteristics predicted responsiveness to T.

Conclusions: In older men with low libido and low T levels, improvements in sexual desire and activity in response to T treatment were related to the magnitude of increases in T and estradiol levels, but there was no clear evidence of a threshold effect.

Trial registration: ClinicalTrials.gov NCT00799617.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Erectile Dysfunction / drug therapy
  • Hormone Replacement Therapy
  • Humans
  • Libido / drug effects
  • Male
  • Placebos
  • Sexual Behavior / drug effects*
  • Sexual Dysfunction, Physiological / blood
  • Sexual Dysfunction, Physiological / drug therapy*
  • Sexual Dysfunction, Physiological / physiopathology
  • Surveys and Questionnaires
  • Testosterone / blood
  • Testosterone / therapeutic use*
  • Treatment Outcome


  • Placebos
  • Testosterone

Associated data

  • ClinicalTrials.gov/NCT00799617