Millions of middle-aged and older American men today undergo testosterone therapy (usually prescription gels or patches), four times as many as a decade ago. That’s despite continuing controversy about the safety and effectiveness of this hormone treatment and even about how to define the condition for which it’s usually prescribed, called age-related hypogonadism (“low T” in the ads)—that is, low blood testosterone levels accompanied by undesirable effects such as erectile dysfunction.
Moreover, many of the men being prescribed testosterone don’t actually have a low blood level or haven’t even had the hormone measured, and they have no related symptoms.
Attracted largely by claims from drug companies and “anti-aging” clinics, these men hope that testosterone therapy will give them youthful vigor, better erections, bigger muscles, and better overall health. Meanwhile, they’re in the same kind of uncharted territory women were in before 2002, when the important Women’s Health Initiative (WHI) clinical trial was abruptly halted because it found that menopausal estrogen/progestin therapy posed serious risks.
Here’s the latest news about testosterone, all from August 2015:
A call for better research: FDA researchers discussed the agency’s ongoing concerns about testosterone for age-related hypogonadism in the New England Journal of Medicine. Studies, mostly observational, have produced inconsistent results about the hormone’s safety for this use, especially in respect to cardiovascular disease and mortality rates, with some finding increased risks, some reduced risks and some no effect. Thus, the FDA is requiring the drug companies to conduct large, long-term randomized clinical trials (or preferably one joint trial) on testosterone’s risks and benefits, along the lines of the WHI study on menopausal hormones. This goes along with the FDA’s order that labels on testosterone products carry a stronger warning about the potential risk of heart attacks and strokes. That’s besides the known risks, such as acne, unwanted hair growth, and breast enlargement.
Some good news: The largest observational study yet, published in the European Heart Journal, followed 83,000 healthy U.S. veterans (average age 66) with low testosterone. Those who took testosterone and achieved “normalized” levels actually had a lower risk of heart attacks, strokes, and death over a 14-year period than men not taking testosterone. However, that conflicts with the negative findings of some previous observational studies as well as a clinical trial in 2010 of 209 older men (average age 74, many with chronic diseases), which was halted early when it found far more heart attacks and other cardiovascular events in those using testosterone. As the VA researchers concluded, only large well-designed clinical trials like WHI will be able to truly determine the safety of testosterone therapy.
More seemingly good news: In a clinical trial in the Journal of the American Medical Association involving 300 men (average age 67) with low testosterone levels, use of the hormone patch for three years had no effect on the progression of atherosclerosis compared to a placebo patch. But the study was not large enough to evaluate the risk of heart attacks, so “it should not be interpreted as establishing cardiovascular safety of testosterone use,” the Harvard researchers noted. Interestingly, the men taking testosterone did not experience improved sexual function or quality of life compared to the placebo group.
Before you join the Low T party
The FDA has approved testosterone replacement therapy only for men who have very low blood levels because of medical reasons (such as pituitary or testicular problems or advanced liver disease), for whom the benefits are clear. And yet, the therapy is mostly being prescribed off-label to men whose “low T” is likely a normal result of aging, for whom the benefits are unproven and the potential risks biologically plausible and troubling. Until clinical trials prove testosterone’s safety and efficacy, we suggest you think twice about taking it for “low T,” especially if you have cardiovascular disease or are at elevated risk for it (for instance, because of age, diabetes, or obesity). Don’t automatically blame “low T” if you feel tired or your libido is waning—or because an ad or clinic presents testosterone therapy to you as a veritable fountain of youth.