In case you haven't noticed, testosterone treatments for men are becoming more common. Drug manufacturers have blanketed the airwaves and cable sports channels with commercials about the negative effects of "low T." But a one-minute ad can only tell you so much. Let's look at the whole picture.

As the most important sex hormone in the male body, testosterone plays a key role in libido, energy, muscle mass, bone density and mortality. Testosterone levels naturally drop with age. Low testosterone affects about 20 percent of men over 60, about 30 percent of men over 70, and half of men over 80, reports the American Urological Association. Diabetes, excess weight, stress, hypertension and high cholesterol also can lower testosterone.

Having adequate amounts of testosterone is important for overall health. In fact, men with too little testosterone have a higher risk of dying sooner than those with optimum levels.

A nine-year Australian study of nearly 3,700 men between 70 and 89 years old found that men with the lowest testosterone levels had the highest death rates after adjustments for age, according to the Journal of Clinical Endocrinology & Metabolism. So how can men know whether their levels are too low? And what should they do about it?

Testing testosterone levels

Fatigue, erectile dysfunction and other signs of low T can be caused by any number of health problems, so it's important to see your doctor about these symptoms to get properly diagnosed. If your doctor suspects low T, blood tests will be ordered to check testosterone levels. These tests are typically done more than once because hormone levels fluctuate, either naturally or from taking certain medications.

Balancing the big T

If low testosterone is identified, lifestyle tweaks can ward off further decreases or even boost hormone levels. For example, losing excess weight, lifting weights regularly, cutting back on alcohol use, getting more sleep and reducing stress have all been shown to improve T levels in some men.

When lifestyle changes don't work, hormone therapy may be prescribed to improve sex drive, muscle mass, bone strength, mood and energy. Treatment is fairly simple - the hormone can be delivered with injections, implants, patches, creams or gels. Most men use a gel, which is rubbed into the skin.

It's important to keep in mind that testosterone therapy may not be a good option for everyone. For one thing, the effects of long-term testosterone therapy are not yet known. Some research has suggested that testosterone treatments may increase the risk of heart attack or stroke. Men who have prostate cancer, an enlarged prostate, heart problems, breast cancer or sleep apnea may not be good candidates for hormone therapy.

What about women and testosterone?

Women also produce testosterone, but in much smaller amounts than men. If levels of this hormone are below normal, women may struggle with a loss of libido, fatigue and depression. Currently, the FDA has not approved any testosterone treatments for women. However, off-label use of testosterone therapy for post-menopausal women is relatively common, particularly in women suffering from a low sex drive. Like men, women should discuss the risks and benefits of hormone therapy with a physician and be sure they understand the potential outcomes of treatment.