Medicine has no clear definition of testosterone deficiency, and the FDA is requiring low T therapy manufacturers to prove their products work.
You see the ads everywhere: Men, do you have “low T”?
Worry-inducing they may be, but they refer to a condition very few men actually have.
In the strictest definition, “low testosterone” is called hypogonadism, a condition in which the body produces little to no testosterone. Some 3 to 4 million American men are estimated to have it.
Testosterone production naturally slows in men over their lifespan. The hormone’s levels peak in the late teens and remain high through mid-age, but by age 70, most men are producing 30 percent less testosterone than they did in their teens. Researchers estimate the rate ticks down at about 1 percent a year. Just as the body slows in many ways as it ages, testosterone production does too.
Beyond this most basic information, clarity is hard to find, however. As a 2014 review article published in the journal Urology describes, no firm consensus of “low” or even normal testosterone exists, particularly in reference to aging. Neither is there clear agreement on what type to measure (testosterone circulates through the body in several different forms, and no one’s sure which matters most for particular conditions). To make matters worse, laboratory tests to measure testosterone are not consistently reliable.
Consensus is hard to come by because testosterone levels range widely, not only from person to person, but from day to day and over time. In healthy men, testosterone levels range between 270 and 1,070 nanograms per deciliter (ng/dL). An international statement on testosterone treatment from a variety of groups, including the American Society of Andrology, recommends considering treatment for testosterone replacement at levels below 230 ng/dL, yet some experts suggest treatment at levels of 200 ng/dL, or as high as 350 to 400 ng/dL. The decision to treat is based on the presence of sign and symptoms of low testosterone, in addition to your levels of the hormone.
As the Urology review points out, those broad ranges make it difficult to know when to treat testosterone deficiency, because there’s no clear definition of what constitutes a deficiency. “No large population-based study of T values from healthy, fertile men with normal sexual activity and reproductive function assessed by commonly accepted validation methods” exists, the review notes.
The symptoms of testosterone deficiency are yet another source of confusion. While hypogonadism has often unmistakable effects — shrinking or very small testes, hot flushes, sweating, and gynecomastia (growth of breasts) — those for low testosterone are more vague. They include diminished vitality, depressed mood, decreased activity, lower sexual function, less bone mass, increased body fat, and sleep disturbances. All are common changes encountered in aging.
Such fuzziness means testosterone could be prescribed for virtually any older man — and sales, in fact, have increased dramatically over the past decade. In just three years, from 2010 to 2013, the Food and Drug Administration (FDA) said in a recent analysis, prescriptions for testosterone rose from 1.3 million to 2.3 million. Just half of those receiving a prescription had been diagnosed with hypogonadism. Worse, one in five did not have their testosterone levels tested before or at any time during treatment.
Tracking testosterone levels in the blood is important, because, far from being a fountain of youth, testosterone therapy may pose health risks. In an August 20, 2015, statement in the New England Journal of Medicine, a concerned group of doctors noted that several studies over the past two years have implicated testosterone therapy in increased heart attacks and other cardiac events, which prompted the FDA to put a warning label on the drug earlier this year. Testosterone therapy also increase the risk of prostate cancer.
The FDA is requiring drug companies to conduct a rigorous trial of testosterone’s risks and benefits, the doctors note, but it could take years to see results. In the meantime, unless you have clinically diagnosed hypogonadism, it’s wise to take a pass.
August 24, 2015
Christopher Nystuen, MD, MBA