'Low T' therapy has yet to be proven: FDA

August 20, 2015 by Amy Norton, Healthday Reporter

'Low T' therapy has yet to be proven: FDA
Agency orders makers of popular testosterone supplements to conduct clinical trials.
(HealthDay)—Testosterone supplements have long been marketed to aging men as a fountain of youth and virility, but there is still no proof they are safe or effective, according to the U.S. Food and Drug Administration.

Writing in the Aug. 20 edition of the New England Journal of Medicine, FDA officials said that only controlled can show whether benefit from treatment to reverse age-related dips in testosterone.

The agency is now requiring product manufacturers to conduct those trials.

As it stands, testosterone supplements are approved only for men with certain medical conditions that cause abnormally low levels of the hormone—such as damage to brain areas that control testosterone production.

But once the FDA approves a drug, doctors are free to prescribe it as they see fit. And most American men on have no clear medical condition; they're using it to counter the aging process, the researchers said.

Between 2009 and 2013, the number of U.S. men on testosterone shot up from 1.3 million to 2.3 million, according to the FDA. And the most common reason, the agency says, is the vague diagnosis of "testicular hypofunction, not elsewhere classified."

That explosion in testosterone use has occurred despite a lack of evidence showing it is effective. The surge has been attributed to an aggressive marketing campaign by manufacturers alerting men to the potential effects of "low T," such as fatigue, sexual dysfunction, declining muscle mass and gains in body fat.

"The benefits and risks of testosterone therapy have not been established for the treatment of men who have due to aging, even if there are symptoms that seem related to the low testosterone," said Dr. Christine Nguyen, lead author of the FDA report and the agency's deputy director of safety.

Typically, a man's slowly decline with age. And there is a "rough correlation" between that decline and symptoms such as sexual dysfunction, said Dr. Bradley Anawalt, an endocrinologist and professor of medicine at the University of Washington, in Seattle.

But it's not clear whether "low T" or other factors—such as chronic health conditions, medications or the aging process itself—are to blame. And it's unlikely, Anawalt said, that men with modestly low testosterone levels would get any benefit from supplements.

What's more, concerns persist that testosterone supplements increase a man's risk of heart attack or stroke. Last March, the FDA started requiring all prescription testosterone products to carry a warning about those potential hazards.

Still, the evidence is mixed. One recent study found that men given a were no more likely to develop hardening of the heart arteries over three years, compared to men given a placebo gel that contained no medicine.

The study did not look at rates of heart attack or stroke, however. Only further clinical trials can show whether those risks are real, the FDA says.

There are other issues, as well. For one, Anawalt said, an older man's testosterone is considered "low" if it falls below the normal range for a healthy young man. There are no standards on normal levels for specific age groups.

"It's just been assumed that the normal range for young men applies to older men, too," Anawalt said.

What's more, FDA research has found that many men do not have any done before getting a prescription for supplements.

And while it is not clear if testosterone is dangerous for men's hearts, there's also little evidence that it benefits their well-being, Nguyen pointed out.

The recent study that found no ill effects on men's heart arteries also found no improvement in sexual function.

Anawalt said that for men with medical conditions that limit testosterone production, it's "pretty clear" that supplements can be helpful. "The question remains," he said, "what do you do with the much larger group of men who have 'low T' related to aging?"

Based on what's known, Anawalt said, supplements are "unlikely to do much" for most men whose dips solely due to age.

Explore further: Testing testosterone: Trial finds no link to hardening of the arteries

More information: The FDA has more information on testosterone supplements.

Related Stories

Testing testosterone: Trial finds no link to hardening of the arteries

August 11, 2015
Testosterone sales have grown rapidly over the last decade, but few studies have examined the long-term effects of taking testosterone on cardiovascular health and other important outcomes. This week, investigators from Brigham ...

More specialists question safety of testosterone therapy for older men

February 17, 2014
(HealthDay)—Following the recent announcement from the U.S. Food and Drug Administration about the potential hazards of using testosterone supplements in older men, another group of experts is raising concerns about the ...

FDA warning: men's testosterone drugs overused (Update)

March 3, 2015
The Food and Drug Administration is warning doctors against over-prescribing testosterone-boosting drugs for men, saying the popular treatments have not been established as safe or effective for common age-related issues ...

New recommendations addresses the diagnosis and management of testosterone deficiency

July 9, 2015
An expert panel convened by the International Society for Sexual Medicine has developed a detailed "Process of Care" for the diagnosis and management of testosterone deficiency in men.

Testosterone therapy fails to treat ejaculatory dysfunction

July 9, 2015
Men who have ejaculatory disorders and low testosterone levels did not experience improved sexual function after undergoing testosterone replacement therapy, according to a new study published in the Endocrine Society's Journal ...

Study of 83,000 veterans finds cardiovascular benefits to testosterone replacement

August 10, 2015
A Veterans Affairs database study of more than 83,000 patients found that men whose low testosterone was restored to normal through gels, patches, or injections had a lower risk of heart attack, stroke, or death from any ...

Recommended for you

Genetic changes associated with physical activity reported

December 10, 2018
Time spent sitting, sleeping and moving is determined in part by our genes, University of Oxford researchers have shown. In one of the most detailed projects of its kind, the scientists studied the activity of 91,105 UK Biobank ...

Study may offer doctors a more effective way to treat neuroblastoma

December 7, 2018
A very large team of researchers, mostly from multiple institutions across Germany, has found what might be a better way to treat patients with neuroblastoma, a type of cancer. In their paper published in the journal Science, ...

Progress made in transplanting pig hearts into baboons

December 6, 2018
A large team of researchers from several institutions in Germany, Sweden, Switzerland and the U.S. has transplanted pig hearts into baboons and kept them alive for an extended period of time. In their paper published in the ...

'Chemo brain' caused by malfunction in three types of brain cells, study finds

December 6, 2018
More than half of cancer survivors suffer from cognitive impairment from chemotherapy that lingers for months or years after the cancer is gone. In a new study explaining the cellular mechanisms behind this condition, scientists ...

Hybrid prevalence estimation: Method to improve intervention coverage estimations

December 6, 2018
LSTM's Professor Joseph Valadez is senior author on a new study published today in the Proceedings of the National Academy of Sciences, which outlines proposals for a more accurate estimator of health data.

World's smallest wearable device warns of UV exposure, enables precision phototherapy

December 5, 2018
The world's smallest wearable, battery-free device has been developed by Northwestern Medicine and Northwestern's McCormick School of Engineering scientists to measure exposure to light across multiple wavelengths, from the ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.