A Harvard expert shares his thoughts on testosterone-replacement therapy
A meeting with Abraham Morgentaler, M.D.
It could be said that testosterone is what makes guys, guys. 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% per year, starting in the 40s. As men get in their 50s, 60s, and beyond, they may start to have symptoms and signs of low testosterone like lower libido and sense of vitality, erectile dysfunction, decreased energy, decreased muscle mass and bone density, and anemia. Taken together, these symptoms and signs are often called hypogonadism ("hypo" meaning low working and"gonadism" referring to the testicles). Yet it is an underdiagnosed issue, with only about 5 percent of those affected undergoing therapy.
But little consensus exists about what constitutes low testosterone, when testosterone supplementation makes sense, or what risks patients face.
He has developed specific expertise in treating lower testosterone levels. In this interview, Dr. Morgentaler shares his views on current controversies, the treatment plans 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 the typical man to find a physician?
As a urologist, I tend to observe men because they have sexual complaints. The main hallmark of low testosterone is low sexual libido or desire, but another can be erectile dysfunction, and some other man who complains of erectile dysfunction should possess his testosterone level checked. Men may experience other symptoms, like more difficulty achieving an orgasm, less-intense orgasms, a much smaller amount of fluid out of ejaculation, and a feeling of numbness in the penis when they see or experience something which would usually be arousing.
The more of these symptoms you will find, the more probable it is that a man has low testosterone. Many physicians tend to discount those"soft symptoms" as a normal part of aging, but they are often treatable and reversible by decreasing testosterone levels.
Aren't those the same symptoms that guys have when they're treated for benign prostatic hyperplasia, or BPH?
Not exactly. There are quite a few medications which may lessen sex drive, including the BPH drugs finasteride (Proscar) and dutasteride (Avodart). Those drugs may also decrease the amount of the ejaculatory fluid, no wonder. However a reduction in orgasm intensity usually does not go together with therapy for BPH. Erectile dysfunction does not ordinarily go along with it either, though certainly if somebody has less sex drive or less attention, it is more of a challenge to have a good erection.
How do you decide whether or not a man is a candidate for testosterone-replacement treatment?
There are two ways we determine whether somebody has low testosterone. One is a blood test and the other is by characteristic symptoms and signs, and the correlation between these two approaches is far from perfect. Normally men with the lowest testosterone have the most symptoms and guys with highest testosterone have the least. However, there are some guys who have low levels of testosterone in their blood and have no signs.
Looking at the biochemical numbers, The Endocrine Society* believes low testosterone for a total testosterone level of less than 300 ng/dl, and I believe that's a reasonable guide. However, no one quite agrees on a few. It is not like diabetes, where if your fasting glucose is above a certain level, they'll say,"Okay, you've got it." With testosterone, that break point isn't quite as clear.
| *Note: The Endocrine Society recommends clinical practice guidelines with recommendations for who should and should not receive testosterone therapy. For a complete copy of the guidelines, log on to www.endo-society.org. check it out Is total testosterone the right thing to be measuring? Or should we be measuring something different? This is just another area of confusion and good discussion, but I do not think that it's as confusing as it is apparently from the literature. When most doctors learned about testosterone in medical school, they heard about overall testosterone, or all of the testosterone in the human body. But about half of the testosterone that's circulating in the blood isn't readily available to cells. It is closely bound to a carrier molecule known as sex hormone--binding globulin, which we abbreviate as SHBG. The biologically available part of total testosterone is called free testosterone, and it is readily available to cells. Though it's just a little portion of this total, the free testosterone level is a pretty good indicator of reduced testosterone. It is not ideal, but the correlation is greater than with testosterone. This professional organization recommends testosterone therapy for men who have
Therapy Isn't recommended for men who have
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