A Harvard Specialist shares his Ideas on testosterone-replacement therapy
It might be said that testosterone is the thing that makes men, men. It gives them their characteristic deep voices, big muscles, and facial and body hair, differentiating them from women. It stimulates the development of the genitals at puberty, 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 assists cognition.
As time passes, the testicular"machinery" that 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 may start to have symptoms and signs of low testosterone such as lower libido and sense of vitality, erectile dysfunction, decreased energy, decreased muscle mass and bone density, and nausea. Taken together, these signs and symptoms are often referred to as hypogonadism ("hypo" significance low functioning and"gonadism" referring to the testicles). Yet it is an underdiagnosed issue, with just about 5% of those affected undergoing therapy.
Various studies have shown that testosterone-replacement therapy may provide a vast range of benefits for men with hypogonadism, including enhanced libido, mood, cognition, muscle mass, bone density, and red blood cell production. Much of the current debate focuses on the long-held belief that testosterone may 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 has developed specific experience in treating lower testosterone levels. In this interview, Dr. Morgentaler shares his views on current controversies, the treatment strategies he uses with his own patients, and he thinks specialists should rethink the potential connection between testosterone-replacement therapy and prostate cancer.
Symptoms and diagnosisWhat signs and symptoms of low testosterone prompt the average person to find a physician?
As a urologist, I tend to see men because they have sexual complaints. The primary hallmark of low testosterone is reduced sexual libido or desire, but another may be erectile dysfunction, and some other guy who complains of erectile dysfunction should get his testosterone level checked. Men may experience other symptoms, such as more difficulty achieving an orgasm, less-intense orgasms, a lesser quantity of fluid out of ejaculation, and a sense of numbness in the manhood when they see or experience something which would usually be arousing.
The more of the symptoms you will find, the more probable it is that a man has low testosterone. Many physicians often discount those"soft symptoms" as a normal part of aging, but they are often treatable and reversible by normalizing testosterone levels.
Aren't those the same symptoms that men have when they're treated for benign prostatic hyperplasia, or BPH?
Not exactly. There are a number of medications which may reduce libido, such as the BPH medication finasteride (Proscar) and dutasteride (Avodart). Those drugs may also reduce the amount of the ejaculatory fluid, no question. But a reduction in orgasm intensity usually does not go together with therapy for BPH. Erectile dysfunction does not ordinarily go together with it either, though certainly if somebody has less sex drive or less interest, it is more of a struggle to have a good erection.
How do you determine whether a person is a candidate for testosterone-replacement treatment?
There are just two ways that we determine whether somebody 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. Normally guys with the lowest testosterone have the most symptoms and guys with maximum testosterone have the least. But there are a number of guys who have reduced levels of testosterone in their blood and have no symptoms.
Looking purely at the biochemical amounts, The Endocrine Society* believes low testosterone to be a total testosterone level of less than 300 ng/dl, and I think that is a sensible guide. However, no one quite agrees on a few. It is not like diabetes, where if your fasting sugar is above 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 publishes clinical practice guidelines with recommendations for who internet should and should not receive testosterone therapy. For a complete copy of the instructions, log on to www.endo-society.org. Is total testosterone the ideal thing to be measuring? Or if we are measuring something different? Well, this is just another area of confusion and great debate, but I do not think it's as confusing as it appears to be from the literature. When most doctors learned about testosterone in medical school, they learned about overall testosterone, or all the testosterone in the body. However, about half of their testosterone that's circulating in the blood isn't available to cells. It's closely bound to a carrier molecule called sex hormone--binding globulin, which we abbreviate as SHBG. The biologically available portion of total testosterone is known as free testosterone, and it's readily available to cells. Even though it's just a small portion of the overall, the free testosterone level is a pretty good indicator of reduced testosterone. It's not ideal, but the correlation is greater compared to total testosterone.
Do time daily, diet, or other factors influence testosterone levels? For years, the recommendation was 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 demonstrated little change in blood testosterone levels in men 40 and mature within 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 affect diagnosis. Most guidelines nevertheless say it is important to do the evaluation in the morning, however for men 40 and above, it probably 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 dietary supplements. For example, it seems that those who have a diet low in protein have lower testosterone levels than men who consume more protein. But diet has not been researched thoroughly enough to create any clear recommendations.
What forms of testosterone-replacement therapy are available? * The earliest form is the injection, which we use because it's inexpensive and because we faithfully become fantastic testosterone levels in nearly everybody. The disadvantage is that a man needs to come in every few weeks to get a shot. A roller-coaster effect may also happen as blood glucose levels peak and then return to baseline. [See"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 high rate of skin irritation. In one study, as many as 40 percent of people that used the patch developed a red area on their skin. That limits its usage. The most widely used testosterone preparation in the United States -- and the one I begin almost everyone off -- is a topical gel. The gel comes in tiny tubes or within a special dispenser, and you rub it on your shoulders or upper arms once a day. Based on my experience, it has a tendency to be absorbed to good degrees in about 80% to 85 percent of men, but leaves a substantial number who don't consume enough for it to have a favorable impact. [For specifics on various formulations, see table ] Are there any drawbacks to using dyes? How long does it take for them to get the job done? Men who start using the gels have to return in to have their testosterone levels measured again to make certain they're absorbing the proper quantity. Our target is that the mid to upper range of normal, which generally means approximately 500 to 600 ng/dl. The concentration of testosterone in the blood really goes up quite quickly, in just several doses. I usually measure it after 2 weeks, although symptoms may not change for a month or two. |