What is Testosterone?
Testosterone is the male sex hormone that is made in the testicles. Testosterone hormone levels are important to normal male sexual development and functions.
During puberty (in the teen years), testosterone helps boys develop male features like body and facial hair, deeper voice, and muscle strength. Men need testosterone to make sperm. Testosterone levels generally decrease with age, so older men tend to have low blood testosterone levels.
What is Low Testosterone?
Some men have low testosterone levels. This is called testosterone deficiency (TD) or often referred to as Low Testosterone (Low-T).
The American Urology Association (AUA) identifies low blood testosterone (Low-T) as less than 300 nanograms per deciliter (ng/dL) on two tests obtained in the morning. Several symptoms or conditions may accompany TD:
- Low sex drive
- Reduced lean muscle mass
- Erectile dysfunction
- There are many other possible reasons for these symptoms, such as: opioid use, some congenital conditions (medical conditions you are born with), loss of or harm to the testicles, diabetes, and obesity (being overweight). See your doctor if you have any of these symptoms.
Why Testosterone Therapy (TT)?
You may benefit from testosterone therapy (TT) if you have TD and bothersome symptoms (described above). In some cases, TT is strongly recommended, such as with certain conditions you are born with (i.e. Klinefelter syndrome) or if the testicles are removed or lost due to surgery, trauma, infection, or other similar issues. The FDA has approved TT as a replacement for men with low T due to disorders of the testicles, pituitary gland, or brain which result in low T.
Although the use of TT in men with declining T levels due to aging or other conditions is not specifically approved by the FDA, it is commonly prescribed for these conditions "off-label." Speak with your physician to determine if you may benefit from TT, including which type of treatment is most appropriate.
TT may help you but it is also linked to certain (potentially harmful) side effects. (See discussion of these side effects below.) Some of these side effects are definitely linked to TT, while others remain debatable. One area of ongoing debate is whether TT may increase the risk for heart disease or stroke in certain men.
Based on data from a few clinical studies, the Federal Drug Administration (FDA) required that testosterone drug labels should state that there is a risk for heart disease and stroke for some men using testosterone products. All men should be checked for heart disease and stroke before, and periodically while on, TT. The AUA however, on careful review of evidence-based peer review literature, has stated that at the current time, it is not clear if TT increases or decreases the risk for cardiovascular events, such as cardiovascular disease or strokes.
How Common is Low Testosterone in Men?
It is hard to know how many men among us have low T, although data suggest that overall about 2.1% (about 2 men in every 100) may have low T. As few as 1% of younger men may have low T, while as many as 50% of men over 80 years old may have low T. People who study the condition often use different cut-off points for the numbers, so you may hear different numbers being stated.
Low T is more common in men who have diabetes or who are overweight. In one research study, 30% of overweight men had low T, compared to only 6.4% of those with normal weight. The same study found diabetes to be a risk factor for low T. In another study, 24.5% of men with diabetes had low T, compared to 12.6% of those without diabetes.