Low testosterone (hypogonadism) occurs when a man produces less testosterone than is medically normal. In most men, testosterone levels decrease over time, so lower levels are commonly found in men beginning in their mid-40s.
Testosterone levels vary by age. According to many doctors, if your levels are below 300 ng/dL, you have low testosterone. While only a blood test can determine your testosterone level, if you have
symptoms of low testosterone, you should ask your doctor if you would benefit from a complete physical exam and if your testosterone levels should be checked.