An Introduction to Low Testosterone

By Dr. Craig Perlman, Board Certified Endocrinologist

Many notable UFC fighters have been granted therapeutic use exemptions for testosterone replacement therapy, commonly referred to as ‘TRT’. The possibility of an unfair advantage has sparked an ever-increasing controversy over the fairness of the use of testosterone. For example, Michael Bisping, who has expressed opposition to the use of TRT, has lost three title contention fights to fighters who had all received therapeutic exemptions. So let’s delve into some of the basics of why a fighter would pursue testosterone replacement therapy and how would one qualify for this treatment modality.

At some point, as you start getting older, your balls don’t work as well and you don’t make as much testosterone. But, that’s life and you deal with it.
-Michael Bisping

Testosterone, the key male hormone, contains both anabolic and androgenic properties. The anabolic effects conferred by testosterone consist of an increase in muscle mass and strength, and erythrocytosis, which is an increase in red blood cell quantity. This, in turn, will result in an increase in cardiovascular endurance. Androgenic effects include male pattern baldness, increase in body hair and aggression.

Basically, to qualify for testosterone replacement therapy, an individual must display both clinical symptoms of low testosterone as well as biochemical evidence of low serum testosterone levels. Laboratories differ in reference ranges for testosterone, which are based on a morning blood draw of a healthy 20 year old male. Studies have demonstrated a decline of 2% per year in men aged 40 years onward. Clinical symptoms of testosterone deficiency include muscle weakness, diminished libido, erectile dysfunction, fatigue and impairment of cognitive function.

Why would one have a low testosterone level? There are a multitude of reasons, including both congenital and acquired, and consist of disorders at the level of the pituitary gland (located just below the brain), testicles, and androgen receptors located throughout the body.


So that begs the next question: Why would a mixed martial arts fighter who exhibits both physical and mental attributes that seem to contradict any possibility of testosterone deficiency require a therapeutic use exemption? First and foremost, and perhaps controversial, previous anabolic steroid use and subsequent cessation will result in marked suppression in one’s own testosterone production. Should this athlete be approved for TRT? However, recent studies now suggest a connection between repetitive head trauma and low testosterone levels. So, should all fighters qualify for testosterone replacement therapy based on this connection? This question certainly requires further investigation.

This is the first article in a series of articles pertaining to performance enhancing drugs (PEDs) and MMA. The second article can be found here


Dr. Craig Douglas Perlman MD practices in Internal Medicine and Endocrinology, Diabetes & Metabolism.