How Low Testosterone Can Affect Your Sex Drive

by WebMD

Testosterone isn’t the only fuel for a man’s sex drive and performance. But low testosterone can reduce your ability to have satisfying sex. Lack of sex drive and erectile dysfunction are sexual problems that can result from low testosterone. If low testosterone is the cause, treating it can help.

Testosterone and the Causes of Low Libido

Researchers haven’t unraveled the mystery of just how testosterone increases libido. It’s normal for a man’s sex drive to slowly decline from its peak in his teens and 20s, but libido varies widely between men. What one man might consider a low sex drive, another might not. Also, sex drive changes within each man over time and is affected by stress, sleep, and opportunities for sex. For these reasons, defining what’s a “normal” sex drive is next to impossible. Usually, the man himself identifies a lack of sex drive as a problem. Other times, his partner may consider it to be an issue.

Low testosterone symptoms don’t always include feeling like you have no sex drive. Some men maintain sexual desire at relatively low testosterone levels. For other men, libido may lag even with normal testosterone levels. Low testosterone is one of the possible causes of low libido, however. If testosterone is lowered far enough, virtually all men will experience some decline in sex drive.

In a large study of men in Massachusetts, about 11 percent overall said they had a lack of sex drive. The researchers then tested all the men’s testosterone levels. About 28% of men with low testosterone had low libido. These men were relatively young, with an average age of 47; older men might have worse sexual symptoms.

Low testosterone is only one of the causes of low libido. Stress, sleep deprivation, depression, and chronic medical illnesses can also sap a man’s sex drive.

Erectile Dysfunction

Surprisingly, low testosterone by itself rarely causes erectile dysfunction. Low testosterone alone -- with no other health problems -- accounts for a small minority of men with erectile dysfunction.

Erection problems are usually caused by atherosclerosis -- hardening of the arteries. If damaged, the tiny blood vessels supplying the penis can no longer dilate to bring in the strong flow needed for a firm erection. Diabetes, high blood pressure, and high cholesterol are the three main causes of atherosclerosis and erectile dysfunction.

At the same time, low testosterone is a frequent accomplice to atherosclerosis in creating erectile dysfunction. In studies, as many as one in three men mentioning ED to their doctor have low testosterone. Experts believe that in men with other factors causing erectile dysfunction, low testosterone can strongly contribute, making a difficult situation even more difficult.

Strengthening the connection, low testosterone is linked in some way with many of the conditions that lead to erectile dysfunction:

Metabolic syndrome
Obesity
Endothelial dysfunction
Diabetes

Although low testosterone isn’t known to cause them, the associations between other medical conditions and low testosterone can be significant.

Testosterone therapy improves sex drive and satisfaction with sex in many men. However, the long-term risks and benefits of testosterone replacement are unknown. Research trials on testosterone replacement in men are ongoing, although results are years away.

What Low Testosterone Can Mean for Your Health

Researchers are unlocking the mysteries of how low testosterone is related to men’s overall health. Along the way, they’re uncovering connections between low testosterone and other health conditions.

Diabetes, metabolic syndrome, obesity, and high blood pressure have all been linked to testosterone deficiency. Low testosterone isn’t known to cause these health problems, and replacing testosterone isn’t the cure. Still, the associations between low testosterone and other medical conditions are interesting and worth a look.

Low Testosterone: A Marker for Poor Health?

In recent years, researchers have noticed general links between low testosterone and medical conditions. A 2006 study showed that in 2,100 men over age 45, the odds of having low testosterone were:

2.4 times higher for obese men
2.1 times higher for men with diabetes
1.8 times higher for men with high blood pressure

Experts don’t suggest that low testosterone causes these conditions. In fact, it might be the other way around. That is, men with medical problems or who are in poor general health might then develop low testosterone.

Research into the relationship between low testosterone and several other health conditions is ongoing.

Diabetes and Low Testosterone

A link between diabetes and low testosterone is well established. Men with diabetes are more likely to have low testosterone. And men with low testosterone are more likely to later develop diabetes. Testosterone helps the body’s tissues take up more blood sugar in response to insulin. Men with low testosterone more often have insulin resistance: they need to produce more insulin to keep blood sugar normal.

As many as half of men with diabetes have low testosterone, when randomly tested. Scientists aren’t sure whether diabetes causes low testosterone, or the other way around. More research is needed, but short-term studies show testosterone replacement may improve blood sugar levels and obesity in men with low testosterone.

Obesity and Low Testosterone

Obesity and low testosterone are tightly linked. Obese men are more likely to have low testosterone. Men with very low testosterone are also more likely to become obese.

Fat cells metabolize testosterone to estrogen, lowering testosterone levels. Also, obesity reduces levels of sex hormone binding globulin (SHBG), a protein that carries testosterone in the blood. Less SHBG means less testosterone.

Losing weight through exercise can increase testosterone levels. Testosterone supplements in men with low testosterone can also reduce obesity slightly.

Metabolic Syndrome and Low Testosterone

Metabolic syndrome is the name for a condition that includes the presence of abnormal cholesterol levels, high blood pressure, waistline obesity, and high blood sugar. Metabolic syndrome increases the risk for heart attacks and strokes.

Studies show that men with low testosterone are more likely to develop metabolic syndrome. In short-term studies, testosterone replacement improved blood sugar levels and obesity in men with low testosterone. The long-range benefits and risks are still unknown.

Testosterone and Heart Disease

Testosterone has mixed effects on the arteries. Many experts believe testosterone contributes to the higher rates of heart disease and high blood pressure that tend to affect men at younger ages. By this reasoning, high testosterone might be bad for the heart.

But testosterone deficiency is connected to insulin resistance, obesity, and diabetes. Each of these problems increases cardiovascular risk. Men with diabetes and low testosterone also have higher rates of atherosclerosis, or hardening of the arteries.

A certain amount of testosterone may be necessary for healthy arteries because it’s converted into estrogen, which protects arteries from damage. As yet, no studies show that testosterone replacement protects the heart or prevents heart attacks.

Testosterone and Other Conditions

Low testosterone often exists with other medical conditions:

Depression: In a study of almost 4,000 men older than 70, those with the lowest testosterone levels were more than twice as likely to be depressed. This link remained even after allowing for age, general health, obesity, and other variables.
Erectile dysfunction (ED): Problems with erections are one of the most common symptoms of low testosterone. Most ED is caused by atherosclerosis. Men with risk factors for atherosclerosis -- diabetes, metabolic syndrome, or obesity -- often have low testosterone, too.
High blood pressure: The effects of testosterone on blood pressure are many and complex. Men with high blood pressure may be almost twice as likely to have low testosterone as men with normal blood pressure. On the other hand, too much testosterone can increase blood pressure. Testosterone acts in multiple ways on blood vessels, so this may account for the varying effects.

Testosterone Replacement: Deciding on Treatment

The question that remains is, does low testosterone cause or worsen medical problems like diabetes? Or are people who develop diabetes, or other health problems, simply more likely to also have low testosterone?

Studies to answer these questions are under way, but it will be years before we know the results. In the meantime, remember that testosterone replacement hasn’t been conclusively shown to improve any health condition other than testosterone deficiency and its symptoms. For men with low testosterone levels as measured by a blood test who also have symptoms of low testosterone, the decision to take testosterone replacement is one to make with your doctor.

Low Testosterone Explained: How Do You Know When Levels Are Too Low?

Although it’s normal for testosterone levels to drop as men age, low testosterone can affect a man’s health. In many ways, testosterone is the stuff that makes men men. The rush of new testosterone in puberty builds muscle and bone, deepens the voice, and revs up the sex drive. Throughout a man’s life, testosterone maintains his male characteristics.

Testosterone levels decline steadily after age 40. The decline is relatively small, at an average rate of about 1% to 2% percent per year. By middle age and older, virtually all men experience some decline in testosterone -- but only a small percentage of aging men have levels far below those considered normal for their age.

Is this low testosterone part of normal aging -- or a medical problem that needs treatment?

“If a man doesn’t have symptoms, you shouldn’t even test [for low testosterone],” says Karen Herbst, MD, PhD, an endocrinologist with the University of California at San Diego. “There’s no proof that treating low testosterone in the absence of symptoms has any benefits. But in men with symptoms of [low testosterone], many of them will get a benefit from treatment.”

What is Low Testosterone?

Low testosterone is defined as less than 300 nanograms per deciliter of blood. The symptoms of low testosterone include low sex drive, erectile dysfunction, mood problems, fatigue, and sleep disturbances. Of all men with below-normal testosterone levels, about one-half to two-thirds report symptoms.

Unlike a woman’s menopause, when estrogen levels plummet over months to very low levels, men’s “andropause” is a gradual decline of testosterone levels over years. The effects of low testosterone can be insidious, even go unnoticed.

Some men with low testosterone levels have symptoms without recognizing them, Herbst says. “They may still have a sex drive, but not realize how much it’s declined,” she says.

Men with symptoms of low testosterone can have significant impairment in quality of life. Current medical thinking is “these men should be treated with testosterone replacement,” Herbst says.

Low testosterone can be replaced by using a daily skin gel, patches worn on the skin, orally disintegrating tablets, or injections. The general recommendations are to raise the blood testosterone level only into the normal range.

Health Effects of Low Testosterone

Surprisingly little is known about the long-term health effects of low testosterone. Low testosterone is associated with several chronic medical conditions, including obesity, diabetes, depression, and possibly cardiovascular disease. However, “It’s not clear at all that [low testosterone] causes these conditions,” Herbst says. “In fact, it might be the other way around.”

The same processes that lead to medical illness -- causing diabetes and high blood pressure, for example -- could potentially also be causes of low testosterone, says Andre Araujo, PhD, an epidemiologist and researcher on testosterone deficiency. “It’s possible that low testosterone levels serve as a marker of health decline in general,” he says.

Testosterone builds bone, and low testosterone can lead to thinning of the bones, called osteoporosis. Men with hip fractures tend to have low testosterone. As yet, there is no proof that testosterone therapy reduces fracture risk. Still, most physicians would treat a man with low bone density with testosterone, Herbst says.

Testosterone Replacement: Benefits and Risks

Prescriptions for testosterone replacement have risen more than 17 fold in recent years. Some experts applaud the increase, while others sound a note of caution. Testosterone replacement in available doses is felt to be generally safe, but “we just don’t know the long-term benefits or the risks yet,” Herbst says.

Some evidence suggests that many men with symptomatic low testosterone don’t get treated, Araujo says. He and his colleagues found relatively low treatment rates in Boston, in a recent study.

“Only about 12 percent of men with symptomatic androgen deficiency were being treated,” Araujo says. “Without access to the medical data, we can’t say they should have been. But we can say that it didn’t seem to be due to poor access to care or unwillingness on their part.”

Men have a wide variation in response to testosterone replacement. “I wish all guys behaved the same when you give them testosterone,” Herbst says. “They don’t.”

In her specialty clinic, “about 10% of men don’t get much of a response. About 90% see some sort of improvement, and about one in 10 of them are ecstatic,” Herbst says. In clinical studies, the majority of men with low testosterone have improved erectile dysfunction and sex drive with testosterone replacement. The degree of response varies widely, though, and the long-term response isn’t known.

According to the Endocrine Society’s clinical guidelines, certain men shouldn’t take testosterone supplements. Men with metastatic prostate cancer or breast cancer absolutely shouldn’t, because testosterone can stimulate these cancers to grow. Other conditions can potentially be made worse by testosterone therapy, including sleep apnea, severe benign prostatic hypertrophy, severe congestive heart failure, or high red blood cell counts (erythrocytosis).

Testosterone Replacement: Benefits and Risks continued...

Clinical trials to evaluate the benefits of testosterone replacement are underway. Until then, men with low testosterone symptoms whose blood tests show low testosterone levels will need to make their own decisions with their doctors.

That’s if those men can get themselves to speak up about symptoms of low testosterone, though. Herbst says most men in her clinic don’t ask about it. “It would be great if they would,” she says.

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