It is suggested that bioavailable testosterone represents the fraction of circulating testosterone that readily enters cells and better reflects the bioactivity of testosterone than does the simple measurement of serum total testosterone. Also, varying levels of SHBG can result in inaccurate measurements of bioavailable testosterone. Decreased SHBG levels can be seen in obesity, hypothyroidism , androgen use, and nephritic syndrome (a form of kidney disease ). Increased levels are seen in cirrhosis , hyperthyroidism , and estrogen use. In these situations, measurement of free testosterone may be more useful.
If a young man's low testosterone is a problem for a couple trying to get pregnant , gonadotropin injections may be an option in some cases. These are hormones that signal the body to produce more testosterone. This may increase the sperm count. Hedges also describes implantable testosterone pellets, a relatively new form of treatment in which several pellets are placed under the skin of the buttocks, where they release testosterone over the course of about three to four months. Injections and nasal gels may be other options for some men.