• low sex drive;
• low energy;
• erectile dysfunction (difficulty having an erection);
• decreased muscle mass.
There are many other causes of these symptoms. For example, men start losing muscle mass as they get older, even if their testosterone levels are normal. And depression is a common cause of low sex drive, low energy and erectile dysfunction. In fact, most men with these symptoms have causes other than low testosterone.
However, if a man with these symptoms has low blood levels of testosterone, and if these symptoms improve when a man is given testosterone replacement, he is probably experiencing andropause. Testosterone replacement can be given through injections or a patch.
Testosterone treatment has some potential side effects. Most doctors are reluctant to prescribe testosterone for a man who has prostate cancer, or who has several close relatives with prostate cancer. The concern is that the testosterone hormone will encourage cancer cells to grow. The evidence in support of this is, in my opinion, not clear-cut but it's a real concern.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.