First, what is a normal testosterone level? A range between 270 ng/dl and 1070 ng/dl is usually considered normal. But older men tend to have lower levels. In fact, aa major study from here in Massachusetts found that perfectly healthy men aged 60 though 69 had testosterone levels between 196 ng/dl and 859 ng/dl.

Second, was your blood test done early or later in the day? Testosterone levels are highest at 8 a.m. and lowest at 9 p.m. So your blood should be drawn early in the morning to be accurate.

Third, was the right hormone measured? Testosterone travels in the blood in two forms: either bound to proteins, or free and unbound. Free testosterone is the active hormone. To find out if you are low where it counts, your doctor should measure both your free and total testosterone levels.

Finally, what's the meaning of low levels? Let's assume you have a repeat test between 7 a.m. and 10 a.m. And the test shows your levels are low, with a total testosterone below 300 ng/dl and a free testosterone below 5 ng/dl. The next step is to see if you have symptoms of hypogonadism (testosterone deficiency). The main symptoms are low sex drive, osteoporosis or fractures with little trauma. You might also get hot flashes or night sweats.

Other symptoms can include fatigue, loss of muscle mass or height, less facial or body hair, breast enlargement, small testicles, and anemia. If you have many of these symptoms and low testosterone levels, you and your doctor should discuss if testosterone replacement therapy is right for you. Testosterone therapy can enlarge your prostate and potentially cause prostate cancer cells to become more active.