Sex hormone binding globulin (SHBG) is a reproductive hormone produced by the liver that plays a vital role in both male and female reproductive health. It binds and carries sex hormones, particularly testosterone, to the tissues and organs where they are needed. By doing so, SHBG regulates the proportion of sex hormones that are available to be used by your body.
 
Different diseases can cause SHBG levels to rise too high, or fall too low. When this happens, there may be too large or too small a fraction of sex hormones that can have an effect on the body. This makes itself known through a variety of symptoms.