Further Reading

Aromatization & Aromatase Inhibitors

Reaction of a molecule becoming as different molecule

About Aromatase Inhibitors

In the human body, testosterone is converted into estradiol (a type of estrogen) by the enzyme aromatase. This natural process is known as aromatization and occurs at increased levels in aging males. It also occurs to a higher degree when testosterone is introduced exogenously, with increasing amounts of aromatization occurrence intrinsically linked to elevated levels of testosterone. Aromatization results as a response to a spike in testosterone from Testosterone Replacement Therapy and this is controlled through the use of Aromatase Inhibitors (AI). Ideally, the amount of aromatization that occurs from TRT mimics that of naturally occurring aromatization, thus rendering the use of an AI unnecessary, as a certain level of estradiol is required for normal biological function.

The abuse of various anabolic steroid compounds, including ultra/supra physiological levels of Testosterone, invariably results in physically damaging aromatization, unless controlled with Aromatase Inhibitors. Many experienced body-builders understand this, however, many inexperienced steroid users neglect to include an AI with their steroid cycle, and end up causing severe health complications. Aromatization caused by excessive steroid use puts users at risk for extreme damage to the body over a brief time. In contrast, natural aromatization will cause the aging male body to gradually decline in muscle mass and strength over the course of many years.

Normal aromatization serves a primary biological function and is beneficial – it helps the body maintain a healthy balance in terms of temperature, hormonal activity, and mass. It also assists in the synthesis of cholesterol and fats.

Risks from Aromatization in Aging Men

Unfortunately, when males age the amount of aromatase in the body increases, which causes estrogen levels to rise. In extreme cases, estrogen dominance occurs, which can cause a variety of symptoms, including decreased libido and erectile function, enlarged breasts, prostate problems and an increase in abdominal fat. Estrogen dominance can also be a contributory cause of colon, prostate and breast cancer in males.

Improperly Dosed Testosterone

In addition to the issues discussed above (also applicable here)… decreased libido and erectile function, enlarged breasts (gynecomastia), prostate problems and an increase in abdominal fat, etc. etc. Aromatization can also lead to a bloated/swollen appearance, problems with acne, mood instability, and high blood pressure. The improper, unsupervised use of testosterone, specifically when improperly dosed, increases the risk of suffering from excessive aromatization.

The Use of Aromatase Inhibitors

There are three common types of chemicals used to inhibit and/or decrease the body’s production of aromatase: anastrozole, exemestane, letrozole. Each of these drugs has different degrees of efficacy in helping to ameliorate specific symptoms and should be used under a physician’s direction.

Men who experience problems from estrogen dominance have been using aromatase inhibitors to reduce some of the side effects, including fatigue, reduced sexual function, water retention, and depression. In some cases, men have been successfully treated with aromatase inhibitors for gynecomastia, which is a condition that causes enlarged and sensitive male breasts. Bodybuilders use aromatase inhibitors to alleviate symptoms of excess body fat and increases in breast size caused by the misdirected use of anabolic steroids. In some cases, the use of a small dosage of a mild AI is necessary for Testosterone Replacement Therapy treatment.

Final Thoughts


  • High levels of aromatization in men can put them at risk for prostate cancer and heart disease.
  • Age, obesity, alcohol, and insulin can increase aromatase activity.


If you have any questions about Aromatization as it pertains to its integration into TRT, please give us a call to schedule a consultation. We can be reached at (800) 503-4033.