Low testosterone is diagnosed when testosterone levels fall below 250 nanograms per deciliter (ng/dL). The decline in testosterone production is the male equivalent to menopause. However, while women experience a drastic decrease in estrogen at a certain age, the production of testosterone in men decreases gradually. If it decreases more than it should, men can experience a broad range of symptoms.
Testosterone plays a vital role in a man’s libido. As men age, many will experience a decline in sex drive to varying degrees. However, someone with low testosterone will likely experience a more drastic drop in his desire to have sex—which is often noticed by him or his partner. During sex, low levels of testosterone can also make it difficult to achieve an orgasm.
Testosterone stimulates a man’s sex drive and also aids in achieving an erection. Testosterone alone doesn’t cause an erection, but it stimulates receptors in the brain to produce nitric oxide; a molecule that helps trigger an erection. Low testosterone has been linked to many other conditions that cause erectile dysfunction, including obesity, diabetes, and atherosclerosis.
Testosterone plays a role in the production of semen, the fluid that aids in the motility of sperm. It is pretty simple: the more testosterone a man has, the more semen he produces. Men with low testosterone will often notice a decrease in the volume of their sperm during ejaculation.
Testosterone plays a role in several body functions, including hair production. Balding is a natural part of aging for many men, however, men with low testosterone experience a loss of body and facial hair.
Men with low testosterone have reported extreme fatigue and a noticeable decrease in energy levels. If you find yourself tired all of the time, despite getting plenty of sleep, or if you are finding it hard to get motivated to hit the gym or exercise, you might be experiencing symptoms of low testosterone.
Because testosterone plays a role in the building and strengthening of muscle, men with low levels of testosterone might notice a decrease in both muscle mass and strength, especially in their arms, legs, or chest. Those who try to reverse the muscle loss through weight training find it difficult to build or rebuild muscle.
If losing muscle mass was not bad enough, men with low testosterone also experience an increase in body fat. Although the reasons behind this are not entirely clear, research has shown that the genes that control body fat percentage are also responsible for circulating testosterone levels in men.
Men with low testosterone can also experience bone loss; this is because testosterone aids in the production and strengthening of bone. Men with low testosterone, especially older men who have had diminished testosterone levels for some years are more susceptible to bone fractures, usually in the hip, feet, ribs, and wrists.