or more symptoms that are common to both aging and hypogonadism. Further, studies of testosterone therapy in older men generally have been of short duration, involving small numbers of participants, and often lacking adequate controls. In its review of the literature the committee identified only 31 placebo-controlled trials of testosterone therapy in older men. The placebo-controlled trial with the largest sample size involved 108 participants and the duration of therapy in 25 of the 31 trials was 6 months or less. Only one placebo-controlled trial lasted longer than a year. Therefore, assessments of risks and benefits have been limited, and uncertainties remain about the value of this therapy for older men.


Before weighing the options for future research directions, the committee reached several general conclusions that serve as the rationale for its recommendations (Box ES-1). The committee felt that the first and most immediate goal is to establish whether treatment with testosterone results in clear benefits in aging men. In the committee’s determination this could be accomplished in a set of efficacy trials with a study population of older men (65 years and older) who have clinically low testosterone levels and at least one symptom that might be related to low testosterone.

Secondly, given the potential risks of testosterone therapy and the availability of other safe and effective therapeutic intervention options for some of the diseases and conditions it is intended to treat (e.g., bisphosphonates for osteoporosis), the committee felt that testosterone should be considered a therapeutic, not a preventive, measure. Thus, tri-

Key Conclusions and Considerations

  • Focus on the population most likely to benefit.

  • Use testosterone as a therapeutic intervention, not as a preventive measure.

  • Establish a clear benefit before assessing long-term risks.

  • Focus on clinical outcomes in which there is a preliminary suggestion of efficacy and for which safe and effective therapeutic options are not currently available.

  • Ensure safety of the research participants.

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement