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.
We are excited about the FDA’s inquiry into alternative testosterone delivery models. Physicians have been administering testosterone injections in cases of medical necessity since the 1950’s. Clinical research places the therapeutic benefits of testosterone replacement therapy beyond question, in cases where the treatment is medically appropriate and properly managed. The key, like any treatment is to maintain effective protocols and closely monitor the patient’s results, all in conformance with good medical practice.