A Harvard expert shares his thoughts on testosterone-replacement therapy
It could be said that testosterone is the thing that makes guys, men. It gives them their characteristic deep voices, large muscles, and body and facial 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 regular erections. It also boosts the creation of red blood cells, boosts mood, and aids cognition.
Over time, the "machinery" which produces testosterone gradually becomes less powerful, and testosterone levels start to fall, by approximately 1 percent a year, beginning in the 40s. As guys get into their 50s, 60s, and beyond, they may begin to have symptoms and signs of low testosterone such as 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" meaning low working and"gonadism" speaking to the testicles). Yet it is an underdiagnosed issue, with just about 5% of these 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 sexual and reproductive problems. He's developed particular expertise in treating low testosterone levels. In this interview, Dr. Morgentaler shares his views on current controversies, the treatment strategies he uses with his own patients, and he believes experts should reconsider the potential connection between testosterone-replacement therapy and prostate cancer.
Symptoms my latest blog post and pop over to this site diagnosisWhat signs and symptoms of low testosterone prompt the average man to find a doctor?
As a urologist, I have a tendency to observe men since they have sexual complaints. The primary hallmark of low testosterone is reduced sexual desire or libido, but another may be erectile dysfunction, and any guy who complains of erectile dysfunction must get his testosterone level checked. Men can experience different symptoms, such as more difficulty achieving an orgasm, less-intense climaxes, a smaller quantity of fluid out of ejaculation, and a feeling of numbness in the manhood when they see or experience something which 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 discount those"soft symptoms" as a normal part of aging, but they're often treatable and reversible by decreasing testosterone levels.
Aren't those the very same symptoms that guys have when they're treated for benign prostatic hyperplasia, or BPH?
Not exactly. There are quite a few medications that may lessen sex drive, such as the BPH medication finasteride (Proscar) and dutasteride (Avodart). Those drugs can also decrease the quantity of the ejaculatory fluid, no wonder. However a reduction in orgasm intensity usually doesn't go together with therapy for BPH. Erectile dysfunction does not ordinarily go together with it , though certainly if a person has less sex drive or less attention, it's more of a struggle to get a good erection.
How can you determine whether or not a person is a candidate for testosterone-replacement therapy?
There are two ways that we determine whether someone has low testosterone. One is a blood test and the other one is by characteristic signs and symptoms, and the correlation between those two methods is far from perfect. Generally guys with the lowest testosterone have the most symptoms and guys 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* 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 number. It's 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 publishes clinical practice guidelines with recommendations for who should and shouldn't receive testosterone therapy. |
Is total testosterone the right thing to be measuring? Or should we be measuring something else?
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 physicians 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 bloodstream is not available to the cells. It's tightly bound to a carrier molecule called 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 small fraction of this overall, the free testosterone level is a pretty good indicator of low testosterone. It's not ideal, but the significance is greater compared to total testosterone.
Endocrine Society recommendations outlinedThis professional organization recommends testosterone therapy for men who have Therapy is not recommended for men who've
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Do time of day, diet, or other elements influence testosterone levels?
For years, the recommendation has been to get a testosterone value early in the morning since levels start to drop after 10 or even 11 a.m.. But the data behind this recommendation were drawn from healthy young men. Two recent studies showed little change in blood glucose levels in men 40 and older within the course of this day. One reported no change in average testosterone till after 2 Between 6 and 2 p.m., it went down by 13%, a modest sum, and probably not enough to affect identification. Most guidelines still say it is important to perform the test in the morning, however for men 40 and over, it probably does not matter much, as long as they obtain their blood drawn before 6 or 5 p.m.
There are some rather interesting findings about diet. For instance, it appears that those who have a diet low in protein have lower testosterone levels than males who consume more protein. But diet has not been studied thoroughly enough to make any clear recommendations.
Exogenous vs. endogenous testosteroneWithin this guide, testosterone-replacement therapy refers to the treatment of hypogonadism with exogenous testosterone -- testosterone that's manufactured outside the body. Based on the formula, treatment can cause skin irritation, breast tenderness and enlargement, sleep apnea, acne, reduced sperm count, increased red blood cell count, and additional side effects. In a recent prospective study, 36 hypogonadal men took a daily dose of clomiphene citrate for three or more months. Within four to six weeks, each one the men had increased levels of testosterone; none reported some side effects during the entire year they were followed. Since clomiphene citrate is not accepted by the FDA for use in men, little information exists regarding the long-term effects of taking it (such as the risk of developing prostate cancer) or if it's more effective at boosting testosterone than exogenous formulas. But unlike exogenous testosterone, clomiphene citrate maintains -- and potentially enhances -- sperm production. That makes medication like clomiphene citrate one of only a few options for men with low testosterone that want to father children. What kinds of testosterone-replacement treatment are available? * The oldest form is the injection, which we use since it's inexpensive and because we faithfully become good testosterone levels in nearly everybody. The drawback is that a person should come in every few weeks to get a shot. A roller-coaster effect may also happen as blood testosterone levels peak and then return to baseline. Topical therapies help maintain a more uniform level of blood glucose. The first form of topical therapy has been a patch, but it has a quite high rate of skin irritation. In one study, as many as 40 percent of people that used the patch developed a reddish area in their skin. That restricts its use. The most commonly used testosterone preparation in the United States -- and the one I start almost everyone off with -- is a topical gel. There are two brands: AndroGel and Testim. According to my experience, it tends to be absorbed to good levels in about 80% to 85% of men, but leaves a substantial number who don't consume sufficient for this to have a favorable impact. [For details 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're absorbing the right quantity. Our target is the mid to upper assortment of normal, which usually means approximately 500 to 600 ng/dl. The concentration of testosterone in the blood actually goes up quite fast, in just several doses. I normally measure it after two weeks, though symptoms may not change for a month or two. |