Testosterone is one of the most important, but commonly misrepresented hormones found in the body. Most of the information provided to the public comes from exposes on professional athletes. Who can forget Marion Jones relinquishing her medals from the 2000 Olympics after admitting to using performance-enhancing steroids? This unfortunate trend has overshadowed the beneficial side of these hormones.

Testosterone is a messenger for the body. Like most hormones, it is involved in several different body processes both directly and indirectly. Testosterone levels naturally begin a slow decline around age 30, but several factors can alter this rate. Obesity, for instance, can increase the risk of low testosterone, which can make it more difficult to lose weight. Exercise is thought to improve and maintain healthier testosterone production with age.

As levels of testosterone decline, various symptoms may arise. Men may experience fatigue, weight gain, loss of libido (interest in sex), decreased mental sharpness, loss of motivation, mood swings or irritability and declining muscle mass. Research has linked declining testosterone values to several chronic diseases and risk factors, including heart disease and vascular disease [Source: Phillips, Muller]. Lower testosterone also correlates with worsening blood sugar levels in diabetics and decreased heart strength (contractility) [Source: Swartberg, Dobrzycki]. Other studies have shown worse heart function in men with lower free testosterone levels [Source: Dobrzycki]. Finally, there is an overall increased mortality rate among men with lower testosterone values [Source: Shores]. One study has even shown that certain men with lower testosterone levels may be at risk for more aggressive prostate cancer than those with higher testosterone levels. [Source: Morgentaler]

Returning hormone levels to a normal range can have profound positive effects. Many men will notice improved strength and endurance, as well as a return of libido and improved sexual function. Benefits also include improvements in symptoms associated with heart failure and improved stability and balance (essential to those with weak bones) [Source: Pugh, Orwoll]. With impressive supportive data, supplementation warrants attention from all men.

Testosterone levels can be checked through blood, urine or saliva, with blood tests being the most common medium. Evaluations of testosterone levels include a free and a total testosterone reading. Much of the hormone in the bloodstream is bound to a protein, rendering it inactive. The active portion, called “free testosterone,” can give a more accurate picture of how much testosterone is available to the body.

With so many symptoms associated with low testosterone, why is it not supplemented more frequently? Testosterone research has gone through quite a learning curve. Early synthetic versions proved intolerable when they were administered orally, which can often be hard on the liver. Experts began to worry that testosterone was actually harmful. Now the hormone is typically given through the skin, commonly in gel, cream or patch form. Injections are also available, which allows direct blood access, bypassing the liver and preventing complications.

Testosterone is not exclusively a male hormone. Women also have testosterone, but in smaller amounts. Females low on the hormone might also notice benefits with therapy that include greater libido and motivation. Stamina, mood and metabolism may clinically improve with treatment as well.

Current practice states that men with prostate cancer should not receive testosterone as it is thought to accelerate an active case. Note that testosterone is not thought to cause prostate cancer, but may speed up the severity of the disease. Men who are, or have been treated for prostate cancer are at risk for the fatigue and decreased libido of low testosterone as well. Since hormone replacement is typically not recommended for this group, other options are needed. A special combination of two forms of the nutritional supplement carnitine has shown equal effectiveness in battling fatigue and maintaining well being [Source: Cavallini]. This combination contains 2,000 mg of acetyl L-carnitine and 2,000 mg of propionyl L-carnitine.   The heart benefits that are seen with testosterone replacement have not been studied with this combination.

As is the case with most hormones, testosterone needs to be kept in balance. Men with too much testosterone may notice shrinking of the testicles, and both men and women may see acne or aggravated mood swings with high levels. Testosterone can only be given by prescription from a physician. A treatment program should be frequently monitored through lab tests along with attention to potential side effects.