Testosterone found to boost men’s libido, but experts question how sexual function is scored

Testosterone treatments have been touted as the cure-all for low machismo — but a decade-long, multicenter study published Wednesday indicates that while the treatment can help with some men’s sexual function, the hormone therapy is unlikely to turn them into Hugh Hefners.

Testosterone is a hormone that peaks in men during puberty and decreases with age. It is well-known and accepted that testosterone treatment can benefit men who have hypogonadism, a disease that inhibits the body’s ability to produce the hormone. But what about men who have low levels of testosterone simply because they are old?

To answer that question, researchers recruited 790 men aged 65 and older who had low levels of testosterone and no diseases that would have caused such a low level of the hormone. These men rubbed their skin daily with either a testosterone gel called AndroGel or an inactive placebo.

The gels and placebos were manufactured by AbbVie, which also provided $15 million in funding for the study. The National Institutes of Health kicked in another $35 million in financial support.

The outcomes were mixed: Men who received testosterone experienced slight improvements in sexual functioning, a measure of walking ability and level of depression compared to the placebo group. But they did not see any change in other physical measures or in fatigue levels.

“The results show that testosterone therapy did yield certain benefits, but at this point their clinical importance is uncertain,” Dr. Eric Orwoll, an endocrinologist at the Oregon Health & Sciences University, wrote in an editorial in the New England Journal of Medicine, where the original study also appeared.

“Therapy was not a panacea, and the findings alone might be insufficient to support a decision to initiate testosterone therapy in symptomatic older men.”

Principal investigator Dr. Peter Snyder, medical director of the University of Pennsylvania’s Pituitary Center, said that the results are clinically meaningful in part because participants reported that their health, sexual desire, walking ability, and energy level changed positively over the course of the study. More men who received testosterone said that they perceived a change of “much better” or “little better” in these measures than the men who received the placebo.

“If they say they’re better and it’s statistically significant, I’d say it’s better,” he told STAT.

Snyder reported receiving consulting fees from Watson Laboratories, which received approval for a generic version of AndroGel that was later involved in a long legal battle over ‘pay for delay’ deals.

Some scientists aren’t convinced by the data, though. “The effects on sexual function, mood, and depression are very small,” said Dr. Steven Woloshin, a professor at the Dartmouth Institute for Health Policy and Clinical Practice. “I’m not sure how meaningful they actually were.”

Dr. Lisa Schwartz, also of Dartmouth, said that this study is “trying to play catch-up” and answer questions that the pharmaceutical companies promoting the treatments should have answered long ago. She and Woloshin recently agreed to serve as expert witnesses in a class action lawsuit against many of these companies relating to the marketing of these testosterone drugs and their side effects.

These controversial treatments have also come under fire from the Food and Drug Administration, which recently demanded that the labels on these products include information from studies showing their use is linked to a possible increase in risk of heart attack or stroke. (The new study did not reveal any major side effects of AndroGel, but it was not designed to address the safety of the therapy.)

In the study, sexual function was measured with three tests, all of which revealed statistically significant gains from the the testosterone treatment.

The main outcome measure asked men to list the frequency in a given day of everything from “anticipation of sex” to “flirting (by others toward you)” to “intercourse.” Three, six, and nine months from the start of the study, the men who received testosterone reported having approximately one more sexual experience every other day compared to the placebo group. By the end of the year-long trial, however, this difference had all but disappeared.

Woloshin said that this is “sort of a funny scale. You get as much credit for flirting as having successful intercourse,” he pointed out.

The other two tests were designed to assess erectile function and sexual desire. The first test showed that the erectile function gains were generally lower than would be expected in elderly men taking Viagra or Cialis, and the second has not been validated in other testosterone trials.

That sexual desire test’s creator, Leonard Derogatis, a psychologist at the Johns Hopkins University School of Medicine who specializes in sexual medicine, said this test, which asks questions about the strength and frequency of participants’ libido and lust, was a “prototype” — a new version of an older test he had developed — and that he was reluctant to provide this new version to the research group.

“But there were a number of friends in the group,” Derogatis said. “And I thought, ‘Well, you never know when you might need a urologist.’ So, I said, ‘OK.’”

The integrity of any study’s conclusions depends in part on the validity of the tests used to generate them. Orwoll wrote in his editorial that the study will “stimulate” controversy. The pun was probably unintentional. But given the uncertainty over the virility metrics, he’s probably right.