Excess Body Fat and Testosterone Deficiency

Having excess body fat can negatively impact testosterone levels in a variety of ways.

The aromatase enzyme which is responsible for converting testosterone into estrogen is housed in fat cells. Excess fat increases aromatase activity leading to a hormonal imbalance that results in higher estrogen and lower testosterone levels. This imbalance then triggers a cascade of hormonal issues which can decrease the production of the signaling hormones that stimulate testosterone production further decreasing testosterone levels. Beyond the direct effect on sex hormones, there are other hormonal disruptions associated with obesity such as insulin and leptin resistance which also impair testosterone production.

Additionally, many other comorbid conditions independently affect testosterone levels. Sleep apnea is one example. Most testosterone production is during sleep with levels being highest in the early morning. When sleep patterns are disrupted this can negatively impact the release of testosterone as well as other hormones. Nonalcoholic fatty liver disease (NAFLD) is another example and occurs when excess fat accumulates in the liver and causes dysfunction. The liver plays an important role in hormone regulation specifically, in this case, in sex hormone binding globulin (SHBG) production which serves as a reservoir for testosterone. To make matters worse many of the hormonal issues that arise with being overweight or obese function in a bidirectional way meaning that they further exacerbate excess fat accumulation.

Correcting a testosterone imbalance can help increase lean body mass and reduce visceral (abdominal) fat. These changes can then improve metabolism and reduce insulin sensitivity which, in turn, further reduces body fat. Beyond that, testosterone replacement therapy (TRT) is known to improve motivation which often results in an enhanced drive to engage in exercise and overall healthy lifestyle habits. Getting to a healthy body weight is essential for optimal hormone function, and TRT can help achieve that goal.