A Harvard Specialist shares his thoughts on testosterone-replacement therapy
It could be stated that testosterone is what makes guys, men. It gives them their characteristic deep voices, big muscles, and facial and body hair, differentiating them from girls. It stimulates the growth of the genitals , plays a role in sperm production, fuels libido, and leads to regular erections. It also boosts the production of red blood cells, boosts mood, and aids cognition.
Over time, the "machinery" that produces testosterone gradually becomes less effective, and testosterone levels begin to fall, by about 1 percent per year, beginning in the 40s. As guys get in their 50s, 60s, and beyond, they may start to have symptoms and signs of low testosterone such as lower libido and sense of energy, erectile dysfunction, decreased 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's an underdiagnosed issue, with only about 5% of these affected undergoing therapy.
But little consensus exists about 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 problems. He has developed particular expertise in treating low testosterone levels. In this interview, Dr. Morgentaler shares his perspectives on current controversies, the treatment plans he utilizes his patients, and why he thinks specialists should rethink the potential connection between testosterone-replacement treatment and prostate cancer.
Symptoms Get the facts and diagnosisWhat signs and symptoms of low testosterone prompt the average man to see a doctor?
As a urologist, I tend to see men because they have sexual complaints. The primary hallmark of low testosterone is low sexual desire or libido, but another can be erectile dysfunction, and any man who complains of erectile dysfunction should get his testosterone level checked. Men can experience other symptoms, like more trouble achieving an orgasm, less-intense climaxes, a much lesser quantity of fluid out of ejaculation, and a sense of numbness in the manhood when they see or experience something which would normally be arousing.
The more of these symptoms there are, the more likely it is that a man has low testosterone. Many physicians tend to dismiss those"soft symptoms" as a normal part of aging, however, they're often treatable and reversible by decreasing testosterone levels.
Are not those the very same symptoms that men have when they're treated for benign prostatic hyperplasia, or BPH?
Not exactly. There are quite a few medications which may reduce libido, such as the BPH drugs finasteride (Proscar) and dutasteride (Avodart). Those drugs can also decrease the amount of the ejaculatory fluid, no wonder. However a decrease in orgasm intensity normally doesn't go together with treatment for BPH. Erectile dysfunction does not usually go along with it , though certainly if somebody has less sex drive or less attention, it is more of a challenge to get a fantastic erection.
How can you determine whether a person is a candidate for testosterone-replacement treatment?
There are two ways that we determine whether somebody has reduced testosterone. One is a blood test and the other is by characteristic symptoms and signs, and the correlation between those two methods is far from ideal. 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 low levels of testosterone in their blood and have no symptoms.
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 is a reasonable guide. However, no one really agrees on a number. It is similar to diabetes, where if your fasting sugar is over a certain level, they'll say,"Okay, you've got it." With testosterone, that break point isn't quite as apparent.
| *Note: The Endocrine Society recommends clinical practice guidelines with recommendations for who should and should not receive testosterone therapy. Watch"Endocrine Society recommendations summarized." |
Is total testosterone the ideal thing to be measuring? Or if we are measuring something else?
This is just another area of confusion and great discussion, but I don't think that it's as confusing as it is apparently in the literature. When most physicians learned about testosterone in medical school, they learned about overall testosterone, or all the testosterone in the human body. But about half of the testosterone that is circulating in the bloodstream isn't available to cells.
The available portion of total testosterone is known as free testosterone, and it's readily available to cells. Nearly every lab has a blood test to measure free testosterone. Though it's only a little fraction of this total, the free testosterone level is a fairly good indicator of low testosterone. It's not ideal, but the correlation is greater compared to total testosterone.
This professional organization urges testosterone therapy for men who have both
- Reduced levels of testosterone in the blood (less than 300 ng/dl)
- symptoms of low testosterone.
Therapy is not Suggested for men who've
- Prostate or breast cancer
- a nodule on the prostate which can be felt during a DRE
- that a PSA greater than 3 ng/ml without further analysis
- 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 daily, diet, or other factors influence testosterone levels?
For many years, the recommendation has been to receive a testosterone value early in the morning because levels start to fall after 10 or 11 a.m.. But the information 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 p.m. Between 2 and 6 p.m., it went down by 13 percent, a small amount, and probably insufficient to affect identification. Most guidelines still say it is important to perform the test in the morning, but for men 40 and over, it likely doesn't matter much, provided that they get their blood drawn before 5 or 6 p.m.
There are a number of rather interesting findings about diet. By way of instance, it appears that individuals that have a diet low in protein have lower testosterone levels than males who eat more protein. But diet hasn't been studied thoroughly enough to make any recommendations that are clear.
Exogenous vs. endogenous testosteroneWithin the following guide, testosterone-replacement treatment refers to the treatment of hypogonadism with exogenous testosterone -- testosterone that is manufactured outside the body. Based upon the formula, therapy can lead to skin irritation, breast enlargement and tenderness, sleep apnea, acne, reduced sperm count, increased red blood cell count, and other side effects. Within four to six weeks, all of the men had heightened levels of testosterone; none reported any side effects during the year they were followed. Because clomiphene citrate is not approved by the FDA for use in males, little information exists regarding the long-term effects of carrying it (such as the probability of developing prostate cancer) or if it's more capable of boosting testosterone compared to exogenous formulas. But unlike adrenal gland, clomiphene citrate maintains -- and possibly enhances -- sperm production. That makes drugs like clomiphene citrate one of just a few options for men with low testosterone that want to father children. |
What forms of testosterone-replacement therapy are available? *
The earliest form is the injection, which we use because it's cheap and since we reliably get good testosterone levels in almost everybody. The drawback is that a person needs to come in every few weeks to find a shot. A roller-coaster effect may also occur as blood testosterone levels peak and then return to research. [Watch"Exogenous vs. endogenous testosterone," above.]
Topical treatments help maintain a more uniform level of blood glucose. The first kind of topical treatment was a patch, but it has a very large rate of skin irritation. In 1 study, as many as 40 percent of men who used the patch developed a red area in their skin. That restricts its use.
The most commonly used testosterone preparation from the United States -- and also the one I start almost everyone off -- is a topical gel. Based on my experience, it tends to be absorbed to great degrees in about 80% to 85% of guys, but that leaves a substantial number who do not absorb enough for this to have a positive impact. [For specifics on various formulations, see table ]
Are there any drawbacks to using dyes? How long does it require them to work?
Men who start using the implants need to come back in to have their own testosterone levels measured again to make certain they're absorbing the right quantity. Our target is that the mid to upper range of normal, which generally means around 500 to 600 ng/dl. The concentration of testosterone in blood actually goes up quite fast, within several doses. I usually measure it after 2 weeks, although symptoms may not change for a month or two.