Results showed that 7 men in each study group experienced major cardiovascular events, including myocardial infarction, stroke, or death from cardiovascular causes during the treatment period, and 2 men in the testosterone group and 9 in the placebo group experienced major cardiovascular events during the following year. Data also delineated no difference between groups in patterns of risk for cardiovascular events.1

However, with respect to adverse events, the researchers noted the number of participants was insufficient to reliably evaluate the effect of testosterone on these risks.

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Clinical Relevance

In an accompanying editorial, Eric S. Orwoll, MD, of the department of medicine at Oregon Health and Science University in Portland, discussed the study’s strengths and limitations as well as the potential clinical implications of the findings.

“The results show that testosterone therapy did yield certain benefits, but at this point their clinical importance is uncertain,” he wrote. “Therapy was not a panacea, and the findings alone might be insufficient to support a decision to initiate testosterone therapy in symptomatic older men.”

He added that while the study confirmed that testosterone therapy improved sexual function, “the benefits were modest, tended to wane in the latter months of the treatment period, and, as the authors note, were not as robust as those of phosphodiesterase type 5 inhibitors.”

Similarly, vitality did not demonstrate significant improvement with testosterone therapy, and improvements in physical performance, mood, and depression were small. Some men may respond better to testosterone therapy, he noted, but at present, there is not a way to identify these candidates. Additionally, firm conclusions regarding testosterone and adverse events could not be drawn due to the sample size.

Moreover, Dr Orwoll highlighted the trial’s stringent recruitment criteria and the similarity among participants. Almost 90% were white, he explained, and many had health problems such as obesity, hypertension, diabetes, and sleep apnea. Consequently, the results may not be generalizable.3

“The report by Snyder et al is likely to stimulate controversy and to engender additional research questions — as did the Women’s Health Initiative with respect to estrogen-replacement therapy,” Dr Orwoll wrote. “Nevertheless, it is a landmark study in the field of men’s health and no doubt a bellwether for additional important contributions from the Testosterone Trials.”

Evan Hadley, MD, director of the National Institute of Aging’s Division of Geriatrics and Clinical Gerontology noted that the results from the other T Trials are highly anticipated.

“The trials’ results indicate that, for older men with low sexual function, testosterone treatment can contribute to improved function,” Dr Hadley said in the press release. “In contrast, though, the results don’t indicate that testosterone treatment for older men with low walking ability or vitality will improve these conditions to a great extent. Additional trial arms tested effects on other aging-related outcomes, and we are looking forward to their results to help provide further insights into testosterone use in older men.”

Dr Hadley also stressed that older men should consult their physicians if considering testosterone therapy.

The study was funded with grants from the National Institute of Aging. AbbVie also provided funding and donated AndroGel and placebo gel. See the study for a full list of financial disclosures.


  1. Snyder PJ, Bhasin S, Cunningham GR, et al; for the Testosterone Trials Investigators. Effects of testosterone treatment in older men. N Engl J Med. 2016;374:611-624. doi:10.1056/NEJMoa1506119.
  2. Liverman C, Blazer D, eds. Testosterone and aging: clinical research directions. Washington, DC: National Academies Press, 2004.
  3. Orwoll ES. Establishing a framework — does testosterone supplementation help older men? N Engl J Med. 2016;374:682-683. doi:10.1056/NEJMe1600196.