A Harvard expert shares his Ideas on testosterone-replacement therapy
An interview with Abraham Morgentaler, M.D.
It could be stated 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 women. It stimulates the growth of the genitals , plays a role in sperm production, fuels libido, and contributes to regular erections. It also fosters the creation of red blood cells, boosts mood, and assists 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 signs and symptoms of low testosterone like lower libido and sense of vitality, erectile dysfunction, diminished 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). Researchers estimate that the illness affects anywhere from two to six million men in the USA. Yet it is 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 uses with his patients, and he thinks experts should reconsider the potential link between testosterone-replacement therapy and prostate cancer.
Symptoms view it nowMore about the author and diagnosisWhat symptoms and signs of low testosterone prompt the typical man to find 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 must get his testosterone level checked. Men can experience different symptoms, such as more trouble achieving an orgasm, less-intense climaxes, a lesser quantity 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 probable it is that a man has low testosterone. Many physicians often dismiss these"soft symptoms" as a normal part of aging, however, they're often treatable and reversible by normalizing testosterone levels.
Aren't 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, including the BPH drugs finasteride (Proscar) and dutasteride (Avodart). Those drugs may also decrease the amount of the ejaculatory fluid, no wonder. But a reduction in orgasm intensity normally doesn't go along with therapy for BPH. Erectile dysfunction does not ordinarily go along with it either, though surely if a person has less sex drive or less interest, it's more of a challenge to have a fantastic erection.
How do you determine if or not a man is a candidate for testosterone-replacement therapy?
There are just two ways we determine whether someone has reduced testosterone. One is a blood test and the other one is by characteristic symptoms and signs, and the correlation between these two methods is far from perfect. Normally men with the lowest testosterone have the most symptoms and men with maximum testosterone possess the least. But there are some guys who have reduced levels of testosterone in their blood and have no symptoms.
Looking purely at the biochemical numbers, The Endocrine Society* believes low testosterone for a entire testosterone level of less than 300 ng/dl, and I think that's a reasonable guide. However, no one really agrees on a few. 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 apparent.
| *Notice: The Endocrine Society publishes clinical practice guidelines with 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?
This is another area of confusion and great debate, but I do not think that 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 their testosterone that's circulating in the blood isn't readily available to 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. Almost every lab has a blood test to measure free testosterone. Even though it's just a little portion of the total, 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.
This professional organization recommends testosterone therapy for men who have
- Low levels of testosterone in the blood (less than 300 ng/dl)
- symptoms of low testosterone.
Therapy is not Suggested for men who've
- Breast or prostate cancer
- a nodule on the prostate which can be felt during a DRE
- a PSA higher than 3 ng/ml without additional evaluation
- a hematocrit greater than 50 percent or thick, viscous blood
- untreated obstructive sleep apnea
- severe lower urinary tract infections
- class III or IV heart failure.
Do time of day, diet, or other factors influence testosterone levels?
For many years, the recommendation has been to get a testosterone value early in the morning since levels begin to drop after 10 or 11 a.m.. However, the data behind that recommendation were attracted to healthy young men. Two recent studies demonstrated little change in blood testosterone levels in men 40 and mature within the course of the day. One reported no change in average testosterone till after 2 Between 2 and 6 p.m., it went down by 13 percent, a modest amount, and probably insufficient to affect diagnosis. Most guidelines nevertheless say it's important to do the evaluation in the morning, but 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 dietary supplements. By way of example, it seems 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 recommendations that are clear.
Exogenous vs. endogenous testosteroneWithin this guide, testosterone-replacement treatment refers to the treatment of hypogonadism with exogenous testosterone -- testosterone that is produced outside the body. Depending upon the formulation, therapy can cause skin irritation, breast enlargement and tenderness, sleep apnea, acne, reduced sperm count, increased red blood cell count, along with other side effects. Within four to six weeks, each one of the guys had heightened levels of testosterone; none reported any side effects throughout the entire year they were followed. Since clomiphene citrate is not accepted by the FDA for use in males, little information exists regarding the long-term effects of carrying it (such as the risk of developing prostate cancer) or if it's more effective at boosting testosterone compared to exogenous formulations. But unlike exogenous testosterone, clomiphene citrate maintains -- and possibly enriches -- sperm production. This makes drugs such as clomiphene citrate one of only a few choices for men with low testosterone that wish to father children. What kinds of testosterone-replacement therapy are available? * The earliest form is the injection, which we still use since it is inexpensive and because we faithfully become good testosterone levels in nearly everybody. The drawback is that a person needs to 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 research. [Watch"Exogenous vs. endogenous testosterone," above.] Topical therapies help maintain a more uniform level of blood glucose. The first kind of topical treatment was a patch, but it has a very high rate of skin irritation. In 1 study, as many as 40 percent of people that used the patch developed a reddish area on their skin. That limits its use. The most widely used testosterone preparation from the United States -- and also the one I begin almost everyone off -- is a topical gel. 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 consume sufficient for it to have a favorable effect. [For specifics on various formulations, see table below.] Are there any drawbacks to using gels? How long does it require them to get the job done? Men who begin using the implants need to return in to have their own testosterone levels measured again to be certain they're absorbing the right amount. Our target is the mid to upper range of normal, which usually means approximately 500 to 600 ng/dl. The concentration of testosterone in blood really goes up quite fast, within a few doses. I usually measure it after two weeks, even although symptoms may not alter for a month or two. |