A Harvard expert shares his thoughts on testosterone-replacement therapy
It could be stated that testosterone is the thing that makes guys, men. It gives them their characteristic deep voices, large muscles, and facial and body hair, differentiating them from girls. It stimulates the growth of the genitals at puberty, plays a role in sperm production, fuels libido, and leads to normal erections. It also boosts the creation of red blood cells, boosts mood, and aids cognition.
As time passes, the "machinery" which makes testosterone slowly becomes less powerful, and testosterone levels start to drop, by approximately 1% a year, starting in the 40s. As men get into their 50s, 60s, and beyond, they might start to have signs and symptoms of low testosterone like reduced sex drive and sense of energy, erectile dysfunction, decreased energy, reduced muscle mass and bone density, and nausea. Taken together, these signs and symptoms are often called hypogonadism ("hypo" meaning low working and"gonadism" referring to the testicles). Yet it is an underdiagnosed issue, with just about 5% of these affected receiving treatment.
But little consensus exists on what constitutes low testosterone, when testosterone supplementation makes sense, or what dangers patients face. Much of the current debate focuses on the long-held belief that testosterone can stimulate prostate cancer.
Dr. Abraham Morgentaler, an associate professor of surgery at Harvard Medical School and the director of Men's Health Boston, specializes in treating prostate diseases and male sexual and reproductive problems. He's developed particular experience in treating low testosterone levels. In this interview, Dr. Morgentaler shares his perspectives on current controversies, the treatment strategies he utilizes his own patients, and he thinks experts should reconsider the potential connection between testosterone-replacement therapy and prostate cancer.
Symptoms and diagnosisWhat symptoms and signs of low testosterone prompt that the average man to find a doctor?
As a urologist, I have a tendency to see men because they have sexual complaints. The main hallmark of low testosterone is low sexual desire or libido, but another may be erectile dysfunction, and any guy who complains of erectile dysfunction should get his testosterone level checked. Men can experience other symptoms, such as more trouble achieving an orgasm, less-intense orgasms, a lesser amount of fluid from ejaculation, and a sense of numbness in the manhood when they see or experience something that would normally be arousing.
The more of these symptoms you will find, the more likely it is that a man has low testosterone. Many physicians tend to dismiss those"soft symptoms" as a normal part of aging, however, they are often treatable and reversible by normalizing testosterone levels.
Are not those the very same symptoms that men have when they're treated for benign prostatic hyperplasia, or BPH?
Not precisely. There are quite a few drugs that may reduce libido, such as the BPH medication finasteride (Proscar) and dutasteride (Avodart). Those drugs can also decrease the quantity of the ejaculatory fluid, no question. However a reduction in orgasm intensity usually doesn't go together with therapy for BPH. Erectile dysfunction does not usually go along with it either, though certainly if a person has less sex drive or less attention, it is more of a challenge to get a good erection.
How do you determine if or not a person is a candidate for testosterone-replacement treatment?
There are two ways that we determine whether somebody has low testosterone. One is a blood test and the other is by characteristic signs and symptoms, and the correlation between these two approaches is far from ideal. Generally men with the lowest testosterone have the most symptoms and men with highest testosterone have the least. But there are some guys who have reduced levels of testosterone in their blood and have no signs.
Looking at the biochemical numbers, The Endocrine Society* considers low testosterone to be a total testosterone level of less than 300 ng/dl, and I think that's a reasonable guide. But no one quite agrees on a number. It's not like diabetes, in which if your fasting sugar is over a certain level, they will say,"Okay, you've got it." With testosterone, that break point isn't quite as apparent.
| *Note: The Endocrine Society publishes clinical practice guidelines with Recommended Reading recommendations for who should and shouldn't receive testosterone therapy. Is complete testosterone the ideal point to be measuring? Or if we are measuring something different? Well, this is another area of confusion and great debate, but I do not think that it's as confusing as it is apparently from the literature. When most physicians learned about testosterone in medical school, they learned about total testosterone, or all the testosterone in the human body. However, about half of their testosterone that's circulating in the bloodstream is not readily available to cells. It's tightly bound to a carrier molecule called sex hormone--binding globulin, which we abbreviate as SHBG. The available part of overall testosterone is known as free testosterone, and it's readily available to the cells. Though it's only a small portion of this overall, the free testosterone level is a pretty good indicator of low testosterone. It is not ideal, but the correlation is greater than with testosterone.
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