Testosterone (T) plays an important role in men’s sex drive, or libido. While many men experience a drop in sex drive as they age, in men with low T levels this may occur suddenly and result in not only decreased interest in sex but an inability to get an erection. Low T libido problems are one of the first signs of abnormally low levels of this hormone in men.
While T doesn’t cause an erection it stimulates receptors in the brain that release a chemical called nitrous oxide. This chemical relaxes the muscles in the penis so that blood can flow into it thus resulting in an erection. The inability to get and maintain an erection is not always caused by low T levels, however. Sometimes other factors can be the cause of erectile dysfunction that are unrelated to the hormone.