Testosterone is one of best known sex hormones. This powerful hormone is responsible for a host of changes in men and women alike, although it’s primarily known for its powerful effects in men.
The vast majority of male testosterone is produced in the testes. Testosterone production is stimulated by signals sent from the pituitary gland, a small gland located at the base of the brain. Once the testes have received the signal to begin testosterone production, the hormone is released into the bloodstream, where it circulates through the body and interacts with a wide range of organ systems. Testosterone production begins in infancy, although the levels are low. During adolescence and puberty, boys experience a surge in testosterone production that results in the development of secondary sexual characteristics, including the growth of body hair, a deepening voice, growth of the penis, and increased muscle mass. Sperm production also begins around this time. Less visible changes are also taking place—fat distribution, red blood cell production, and bone health are all intimately affected by testosterone.
After puberty, testosterone levels level off, but the hormone will continue to have a profound affect on a man’s emotional and physical health throughout his life. It’s also important to note that testosterone levels aren’t stable even after puberty. In fact, they change from day to day and even hour to hour. Testosterone levels tend to be highest in the morning (that’s why early morning erections are common) and lowest at night. In general, the normal testosterone levels in males ranges from 270 to 1,070 ng/dL. After about age 30, however, testosterone production begins a long, slow decline. Some studies have found that the average male experiences a 1-2% decline production in testosterone every year beginning in his mid to early 30s. According to statistics, over thirteen million men in the United States have low testosterone levels.
Aside from aging, there are several factors that can influence the levels of testosterone:
- Diet: A diet rich in refined carbohydrates can lead to chronic elevation of insulin, the hormone that is responsible for moving glucose from the bloodstream into cells for use as fuel. Elevated insulin levels are known to disrupt central hormone pathways in the body, which inhibits the production of testosterone. Moderate alcohol consumption has also been found to decrease the levels of testosterone.
- Environment: Exposure to chemicals such as Bisphenol A (chemical found in hard plastics) and phthalates (used to soften and increase the flexibility of plastics) can lower testosterone levels at all ages.
- Medications: Long-term use of medications for high cholesterol such as statins can lower testosterone levels.
- Stress: Chronic stress raises the levels of the stress hormone cortisol, which suppresses the central hormone pathways.
- Aromatase: Aromatase is an enzyme that converts testosterone into estrogen. This depletes free testosterone levels while increasing estrogen.
- Obesity: Obesity is associated with high blood glucose and elevated insulin, as well as excessive estrogen production (fat is a bioactive substance that produces aromatase, which increases estrogen levels).
- Liver disease: A healthy liver helps remove excess estrogen. If there is any decrease in liver function because of an underlying medical condition, it can affect testosterone levels.
Low Testosterone Effect on the Body. Whatever the cause, declining and low testosterone can have profound effects on a man’s health and well-being.
Symptoms associated with low testosterone include:
- Reduce sex drive
- Erectile dysfunction
- Hot flashes
- Increased body fat
- Decreased muscle mass
- Bone disease
- Development of breast tissue
- Blood lipid disorders
- Mood disorders
- Increased risk of heart attack
- Cognitive decline
- Memory problems
- Lack of motivation
With such a wide range of symptoms, if you suspect low testosterone levels, it’s important to undergo evaluation by a qualified medical professional. Ideally, blood tests to determine testosterone levels should be performed in the morning between 7 a.m. and 10 a.m. If your results are normal and other diseases have been ruled out, it’s a good idea to take the test again. It is of utmost importance to make lifestyle modifications and regularly visit your doctor for evaluation as lack of testosterone can bring significant physical and mental changes.