A Harvard expert shares his Ideas on testosterone-replacement therapy
An interview with Abraham Morgentaler, M.D.
It might be stated that testosterone is the thing that makes men, men. It gives them their characteristic deep voices, big muscles, and body and facial hair, differentiating them from women. It stimulates the growth of the genitals , plays a role in sperm production, fuels libido, and leads to regular erections. It also fosters the creation of red blood cells, boosts mood, and aids cognition.
Over time, the "machinery" which makes testosterone gradually becomes less powerful, and testosterone levels begin to fall, 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 lower sex drive and sense of energy, erectile dysfunction, diminished energy, reduced muscle mass and bone density, and nausea. Taken together, these symptoms and signs are often called hypogonadism ("hypo" significance low functioning and"gonadism" speaking to the testicles). Yet it's an underdiagnosed issue, with only about 5 percent of those affected undergoing therapy.
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 reproductive and sexual difficulties. 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 specialists should rethink the possible connection between testosterone-replacement therapy and prostate cancer.
Symptoms and diagnosisWhat symptoms and signs of low testosterone prompt the typical person to see a physician?
As a urologist, I tend to observe guys because they have sexual complaints. The main hallmark of low testosterone is low sexual libido or desire, but another can 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 penis when they see or experience something that would usually be arousing.
The more of the symptoms there are, the more likely it is that a man has low testosterone. Many physicians tend to discount these"soft symptoms" as a normal part of aging, but they're often treatable and reversible by decreasing testosterone levels.
Aren't those the same symptoms that guys have when they are treated for benign prostatic hyperplasia, or BPH?
Not exactly. There are a number of medications which may lessen sex drive, including the BPH medication finasteride (Proscar) and dutasteride (Avodart). Those drugs may also decrease the amount of the ejaculatory fluid, no wonder. However a decrease 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 a person has less sex drive or less attention, it is more of a struggle to get a good erection.
How do you decide if or not a person is a candidate for testosterone-replacement therapy?
There are two ways that we determine whether somebody has reduced testosterone. One is a blood test and the other one is by characteristic signs and symptoms, and the correlation between these two methods is far from perfect. Generally men with the lowest testosterone have the most symptoms and men with maximum testosterone possess the least. However, there are a number of guys who have reduced levels of testosterone in their blood and have no signs.
Looking purely at the biochemical amounts, The Endocrine Society* believes low testosterone for a entire testosterone level of less than 300 ng/dl, and I believe that is a sensible guide. However, no one really agrees on a few. It is similar to 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.
| *Notice: The Endocrine Society recommends clinical practice guidelines with recommendations for who should and should not receive testosterone treatment. |
Is total testosterone the right point to be measuring? Or if we are measuring something different?
This is just another area of confusion and good discussion, but I don't think it's as confusing as it appears to be in the literature. When most doctors learned about testosterone in medical school, they learned about overall testosterone, or all of the testosterone in the human body. However, about half of the testosterone that's circulating in the bloodstream is not readily available to cells. It's closely bound to a carrier molecule known as sex hormone--binding globulin, which we abbreviate as SHBG.
The available portion of overall testosterone is known as free testosterone, and it's readily available to the cells. Though it's only a small fraction 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 total testosterone.
Endocrine Society recommendations summarizedThis professional organization urges testosterone treatment for men who have both Therapy Isn't Suggested for men who've
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What kinds of testosterone-replacement therapy are available? *
The earliest form is the injection, which we still use because it is inexpensive and because we faithfully become good testosterone levels in nearly everybody. The disadvantage is that a person should come in every couple of weeks to get a shot. A roller-coaster effect can also occur as blood glucose levels peak and return to baseline.
Topical treatments help preserve a more uniform level of blood testosterone. The first form of topical therapy was a patch, but it has a quite large rate of skin irritation. In 1 study, as many as 40% of men who used the patch developed a red area on their skin. That restricts its usage.
The most widely used testosterone preparation from the United States -- and the one I start almost everyone off with -- is a topical gel. There are two brands: AndroGel and Testim. The gel comes in tiny tubes or within a unique dispenser, and you rub it on your shoulders or upper arms once a day. Based on my experience, it tends to be absorbed to good levels in about 80% to 85% of men, but that leaves a substantial number who don't absorb enough for it to have a positive effect. [For specifics on various formulations, see table below.]
Are there any drawbacks to using gels? How long does it take for them to work?
Men who start using the gels have to come back in to have their testosterone levels measured again to be certain they are absorbing the proper quantity. Our goal is that the mid to upper range of normal, which usually means around 500 to 600 ng/dl. The concentration of testosterone in the blood actually goes up quite quickly, in just several doses. I normally measure it after 2 weeks, even though symptoms may not change for a month or two.