A team of researchers from the UCSD School of Medicine and 12 other medical centers in the U.S. found that testosterone treatment for men over 65 improves sexual function, walking ability and mood. The findings were published in the New England Journal of Medicine on Feb. 18.

The scientists partnered with the National Institute on Aging to conduct a coordinated set of seven double-blind, placebo-controlled trials, which the researchers referred to as TTrials. Participants received either skin-applied testosterone gel or placebo gel over the course of a year. The team has only analyzed the first three trials regarding impact on sexual function, physical function and vitality.

In addition, they used previous research that established a correlation between decreased testosterone levels and aging as a framework to conduct this research. Susan Ellenberg, a co-author of the paper and professor of biostatistics at the Hospital of the University of Pennsylvania, told the UCSD Guardian that the team was investigating the effects of testosterone treatment in older men and found evidence regarding its efficacy.

“The purpose was to find out whether testosterone treatment of older men with low testosterone offered any clear benefits,” Ellenberg said. “The findings indicated some modest to moderate benefits.”

Participants who received testosterone reported better sexual function than those who received the placebo and were more likely to report that their walking ability was better. Although testosterone had minimal benefits to vitality, it was associated with considerable benefits with respect to mood and depressive symptoms.

Elizabeth Barrett-Connor, study lead at the UCSD School of Medicine and Distinguished Professor in Family Medicine and Public Health, said the outcome of the research showed positive influences on the aversive effects of inadequate testosterone concentrations.

“Low testosterone levels can result in excessive fatigue, weakness, depression and the loss of sexual drive in men over 65,” Barrett-Connor told the UCSD Newsroom. “The results of the TTrials show for the first time that testosterone treatment of older men who have unequivocally low testosterone levels does have some benefit, including improved walking ability, sexual function and mood, with a decrease in depressive symptoms.”

The Food and Drug Administration has been attempting to restrict overprescription of testosterone gels and injections due to the potentially adverse affects on the human body. Last March, the FDA ordered pharmaceutical companies to clearly label that testosterone supplements are approved only to treat low levels caused by disease or injury, not by normal aging.

Since only three of the seven TTrials have been evaluated, principal investigator of the TTtrials and professor at the University of Pennsylvania School of Medicine Peter J. Snyder pointed out that the final verdict regarding testosterone treatment efficacy will depend on the results of the other four trials as well as risk assessment.

“Decisions about testosterone treatment for these men will also depend on the results of the other four trials — Cognitive Function, Bone, Cardiovascular, and Anemia — and the risks of testosterone treatment,” Snyder said in a press release. “[The findings] should have no immediate effect on prescribing practices.”

Ellenberg added that the FDA seems to be focusing more on determining potential risks of testosterone supplement over the potential benefits.

“This [research] is one of the largest, if not the largest comparative trial [on testosterone],” Ellenberg said. “The FDA is asking for testosterone manufacturers to do a much larger study to assess potential risks.”

In light of the testosterone supplement controversy, professor of Medicine at the Oregon Health and Science University Doctor Eric Orwoll indicated that these findings could lead to further exploring the effects of the hormone in medical treatments.

“[This] report is important, not only because it deals with an essential public health issue but also because the investigators have succeeded in conducting the kind of well-conceived studies that are sorely needed,” Orwoll wrote in his analysis of the paper. “The findings begin to provide a basis for more rational clinical decisions about testosterone use as well as for additional research.”