A Harvard Specialist shares his thoughts on testosterone-replacement therapy
An interview with Abraham Morgentaler, M.D.
It could be said 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 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 start to fall, by approximately 1% a year, starting in the 40s. As men get in their 50s, 60s, and beyond, they might 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 referred to as 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 receiving treatment.
But little consensus exists on what constitutes low testosterone, when testosterone supplementation makes sense, or what risks 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 ailments 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 plans he uses with his patients, and he thinks specialists should rethink the possible connection between testosterone-replacement therapy and prostate cancer.
Symptoms try this site and click here to read diagnosisWhat symptoms and signs of low testosterone prompt the average person to see a physician?
As a urologist, I have a tendency to see guys since they have sexual complaints. The primary hallmark of reduced testosterone is low sexual desire or libido, but another may be erectile dysfunction, and any man who complains of erectile dysfunction must get his testosterone level checked. Men may 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 penis when they see or experience something which would normally 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 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 drugs 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 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 challenge to get a good erection.
How can you decide if a person is a candidate for testosterone-replacement therapy?
There are two ways that we determine whether someone has reduced 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 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 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, where if your fasting glucose is above a certain level, they'll say,"Okay, you've got it." With testosterone, that break point is not 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 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 tightly bound to a carrier molecule called sex hormone--binding globulin, which we abbreviate as SHBG.
The available part of total testosterone is called free testosterone, and it is readily available to cells. Though it's just a small fraction of the overall, the free testosterone level is a fairly good indicator of reduced testosterone. It's not perfect, but the correlation is greater compared to total testosterone.
Endocrine Society recommendations summarizedThis professional organization recommends testosterone treatment for men who have Therapy Isn't Suggested for men who have
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Do time daily, diet, or other elements affect testosterone levels?
For many years, the recommendation was to get a testosterone value early in the morning since levels begin to drop after 10 or even 11 a.m.. However, the data behind this recommendation were attracted to healthy young men. Two recent studies showed little change in blood testosterone levels in men 40 and mature over the course of the day. One reported no change in typical testosterone till after 2 p.m. Between 6 and 2 p.m., it went down by 13 percent, a modest sum, and probably not enough to influence identification. Most guidelines still say it is important to perform the test in the morning, however for men 40 and above, it likely doesn't matter much, provided that they get their blood drawn before 5 or 6 p.m.
There are a number of very interesting findings about diet. By way of example, it seems that individuals that have a diet low in protein have lower testosterone levels than men who consume more protein. But diet hasn't been researched thoroughly enough to make any clear recommendations.
Exogenous vs. endogenous testosteroneWithin this guide, testosterone-replacement therapy refers to the treatment of hypogonadism with adrenal gland -- testosterone that is manufactured outside the body. Depending upon the formula, therapy can cause skin irritation, breast tenderness and enlargement, sleep apnea, acne, reduced sperm count, increased red blood cell count, along with other side effects. Within four to six weeks, all the guys had heightened levels of testosterone; none reported some side effects during the year they had been followed. Because clomiphene citrate is not accepted by the FDA for use in males, little information exists about the long-term ramifications of carrying it (including the risk of developing prostate cancer) or if it's more capable of boosting testosterone than exogenous formulas. But unlike adrenal gland, clomiphene citrate preserves -- and possibly enriches -- sperm production. This makes drugs 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 an injection, which we use because it's cheap and since we faithfully get good testosterone levels in nearly everybody. The disadvantage is that a person should come in every couple of weeks to find a shot. A roller-coaster effect can also occur as blood testosterone levels peak and then return to baseline. [Watch"Exogenous vs. endogenous testosterone," above.]
Topical treatments help preserve a more uniform level of blood testosterone. The first form of topical treatment has been a patch, but it has a quite large rate of skin irritation. In 1 study, as many as 40 percent of men who used the patch developed a red area on their skin. That limits its usage.
The most widely used testosterone preparation from the United States -- and also the one I begin almost everyone off -- is a topical gel. The gel comes from 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 significant number who do not consume sufficient for this to have a favorable impact. [For details on several different formulations, see table ]
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, within a few doses. I normally measure it after 2 weeks, even although symptoms may not alter for a month or two.