Testosterone Replacement Therapy

Testosterone pills, though available, are not recommended by most doctors in this country. Testosterone molecules are rapidly destroyed in the acidic conditions of the stomach and are poorly absorbed. When taken orally, testosterone also impacts the liver, sometimes dangerously so.

The safest ways to deliver testosterone is through the skin with gels or patches or directly into the blood via injections. These approaches differ in how well they create an even, natural level of testosterone.

Injections, which are taken every two to three weeks, produce a spiky pattern of testosterone levels as can be seen by the chart below.

Testosterone Levels from Injections Every Three Weeks

This pattern results in above-normal levels immediately after the injection and below-normal levels in the days before the next injection. Testosterone injections have the following disadvantages:

  • Produce erratic testosterone levels
  • Somewhat painful
  • Involve frequent trips to a doctor’s office if a man is not willing or able to inject himself.
  • Side effects are relatively uncommon, but can include acne or oily skin, sleep apnea (temporary cessation of breathing during sleep, which prompts waking), breast swelling, and softening or shrinking of the testicles.

Patch and gel forms of testosterone, by contrast, produce much more steady and even levels of testosterone, as the graph below shows.

Testosterone Levels from Patches and Gels

The gel form of testosterone is the most popular way to deliver testosterone. The preparation is a clear, quick-drying gel containing 1% testosterone. Two types of testosterone patches are available: One is applied to the scrotum and the other is applied to the back, stomach, thighs or upper arms. The patches begin releasing testosterone through the skin about 30 minutes after being applied.

Gels deliver a steady, even dose of testosterone to the body while allowing users to avoid the undesirable side effects of injections. On the other hand, gels can cause skin irritation or inadvertent transfer of testosterone to others who rub against the gel.

Risks of Using Testosterone Replacement Therapy

Many body tissues are sensitive to testosterone, including muscles, bones, the brain, skin, testicles, blood and the prostate gland. This means that any alterations in testosterone levels can have wide-ranging effects. For men with truly inadequate testosterone, increasing testosterone may be a boon — or, at least, the risks are outweighed by the potential benefits of therapy. For men with normal testosterone levels, increasing testosterone is hazardous. 

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The most familiar risk from boosting testosterone is raising the risk of prostate cancer or prostate enlargement. In truth, the latest research hasn’t pinned down this risk very well because long-term controlled clinical trials have not been done. In a very real sense, medicine is at the same stage with testosterone replacement therapy (TRT) in men as it was with hormone replacement therapy (HRT) for women 20 years ago. That should be a red flag for everyone involved in the current debates over TRT. When hormone replacement therapy was first used with women it was considered very safe and to have many positive attributes, such as being good for the heart and bones. Early, short-term, and preliminary studies seemed to bear this out. But when long-term studies were eventually done, it became clear that HRT increases the risk of certain cancers and is not beneficial for the heart. Because of all this, other treatments are now being used for alleviating menopause symptoms, increasing bone density and ensuring cardiovascular health.

The suggestions that testosterone replacement therapy may increase the risk of prostate problems come from several related lines of evidence. First of all, we know that the prostate is very sensitive to testosterone levels: Testosterone causes prostate growth while eliminating testosterone shrinks the prostate. In fact, various methods of reducing testosterone are used to treat both prostate cancer and benign prostate enlargement. Studies also clearly demonstrate that the prostate grows following testosterone supplementation. Prostate enlargement by itself is not necessarily a problem — it’s only when that growth causes pain or other problems, such as difficulty urinating or an inability to fully empty the bladder, that it needs to be treated. The studies so far have failed to find a correlation between testosterone replacement therapy and any annoying urinary symptoms that sometimes but not always accompany enlargement.

A less well-known effect of boosting testosterone is an increase in the numbers of oxygen-carrying red blood cells. Again, for men suffering from anemia or lack of energy, this effect may be welcome and can increase their energy and endurance. But adding blood cells also makes the blood thicker and more prone to clogging in tiny vessels, so it can theoretically increase the risk for a variety of cardiovascular problems such as heart attack and stroke.

One original concern about the safety of testosterone therapy has dissipated in recent years. Early studies suggested that testosterone replacement therapy hurt the balance of high-density lipoprotein (the so-called “good” cholesterol) to low-density lipoprotein (“bad” cholesterol). But more recent studies suggest that, as long as testosterone levels are held within normal limits, blood lipid profiles are unaffected or may even improve.

Testosterone replacement therapy can sometimes cause other, less potentially serious effects such as increased acne, increased snoring and sleep apnea (sudden waking from a transitory interruption of breathing), softening of the testicles, and breast tenderness or enlargement. It may also speed up male-pattern baldness, though this effect has not been rigorously documented. Whether fertility is affected by testosterone replacement depends on many factors. As a general rule, male infertility is only very seldom caused by low testosterone and boosting testosterone artificially usually reduces fertility. In fact, relatively high levels of testosterone act as a fairly effective form of birth control.

This fact is not widely known. Thousands of men are using testosterone supplements that hurt their fertility. If you’re trying to have a baby with your partner, do not use any nutritional or natural supplements that claim they will boost muscle mass, increase your metabolism or promote growth. All such products can hurt your fertility, ejaculatory function or erectile function.

In certain cases, however, judicious manipulation of testosterone can improve sperm counts, motility and morphology. This is best done by using medications that indirectly boost the body’s production of testosterone rather than using testosterone replacement itself.

The bottom line is that testosterone replacement therapy is a real, potentially valuable treatment for men with below-normal levels, but it poses equally real risks for men with normal levels. Any man considering testosterone replacement therapy of any kind must have his prostate checked beforehand, both with a digital rectal exam and a blood test of levels of prostate-specific antigen (PSA), which is a marker of prostate health. Any man already using testosterone replacement therapy should have these tests every six months. 

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Steve’s Story

How Testosterone Crippled a Body-Builder’s Reproductive System

When Steve came to see me, he was wearing a tight-fitting polo shirt that revealed a heavily muscled torso. He was tan and gave the outward appearance of excellent health. But he had practically no sperm in his semen and his testicles were small and soft. My suspicion that he was using a supplement that boosted his testosterone was confirmed when his blood test results came back: his testosterone level was three times higher than normal.

Here’s how all that extra testosterone had, essentially, crippled his reproductive system. 

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A man’s body (actually certain key parts of his brain) constantly monitors the level of testosterone in his blood. When levels fall, the brain sends signals to the testicles to boost production, and when levels rise, the brain tells the testicles to shut down. Adding extra testosterone, in other words, tricks the brain and causes it to send signals that not only shut down testosterone production, but sperm production as well. The result are smaller, softer testicles, and infertility.

When I explained this to Steve he was shocked. He had no idea. He agreed to stop taking the supplements he was using and I prescribed a medication to help kick-start his body’s natural testosterone production machinery. His sperm count began to come back in three months and by six months it was normal. Several months after that, Steve’s wife became pregnant. Their baby girl was born two years ago. 

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