Testosterone (T) is an important male sexual hormone that promotes the physical changes that commence at the time of puberty including pubic, axillary and facial hair, deepening voice, prominent Adam’s apple and increased bone and muscle mass. Throughout adulthood, testosterone helps maintain libido, masculinity, sexuality, and youthful vigor and vitality.
The lion’s share of testosterone is manufactured in the testicles, although a small percentage is made by the adrenal glands. Healthy men produce 6-8 mg testosterone/day in circadian pattern with a peak in early morning hours and lag in the late afternoon. There is a gradual decline in T that occurs with the aging process—approximately a 1% decrease each year after age 30. The decline will occur in most men, but will not always be symptomatic. Symptoms of low T may include one or more of the following: fatigue, irritability, depression, decreased libido, erectile dysfunction, ejaculatory dysfunction, decreased energy and sense of wellbeing, loss of muscle and bone mass, increased body fat, abnormal lipid profiles. Essentially, low T can accelerate the aging process.
There is a strong relationship between low T and Metabolic Syndrome. Metabolic Syndrome is defined as having three or more of the following: high blood glucose levels; abdominal obesity; high fats (triglycerides); low levels of the “good” cholesterol (HDL); and high blood pressure.
Obesity can have a pivotal role in the process leading to low T. Fat is not just fat—it is a metabolically active endocrine organ that does not just protrude from our abdomens in an inert state. Fat produces pro-inflammatory factors, hormones and immune cells—including cytokines—which function to inhibit T production in the testicles and the release of hypothalamus and pituitary hormones that govern the release of T. Low T is present in about half of obese men. Fat has an abundance of the hormone aromatase, which functions to convert T to the female hormone estrogen (E). The consequence of too much conversion of T to E is the potential for gynecomastia, aka breast enlargement.