Low testosterone levels may be caused by a number of factors. For example – there may be a problem at the level of the hypothalamus or pituitary to produce appropriate amounts of LH and FSH to stimulate testosterone production. Another possibility is that the organs that make testosterone do not function normally or are not able to respond to stimulation by the brain. Also, as mentioned, changes in SHBG can account for the amount of testosterone that is available to exert its effects. When the problem is in the organs that produce testosterone (the ovaries or testes, for the most part), it is called a "primary" problem". In medical terminology, the decrease in normal testosterone production is called "hypogonadism." When the...
