What is Testosterone?
Testosterone is one of the building blocks of human life. Without Testosterone, humans couldn't exist, because Testosterone is the male sex hormone which contributes to the growth, development, and maintenance of male form and function. Testosterone is also produced by women, but in much lower amounts.
Testosterone belongs to a class of hormones known as Androgens, which are hormones (primarily associated with the male physiology) which activate Androgen Receptors. Testosterone is the most important Androgen, and the most potent.
Testosterone and Male Development
Prenatally, Testosterone is responsible for the formation of primary male sex characteristics, most notably the seminal vesicles, prostate, scrotum, testicles, and penis. Exposure to Testosterone during this period is absolutely necessary for full and total normal male development.
Testosterone exposure in late-childhood leads to male puberty, contributing to the physiological changes which turn a boy into a man, including the deepening of the voice, changes in body fat, increase in muscle mass, stimulation of bone growth, the full development of the sex organs, and more.
Whereas Testosterone is responsible for growth and development during the earlier stages of human life, after puberty has concluded, Testosterone no longer encourages growth, but is necessary to maintain health, wellness, and sexual function. Normal Testosterone Levels are directly associated with healthy libido, high fertility, balanced mood, high energy levels, strong bones, and a strong heart.
Types of Low-T
Low-T is a condition in which the body does not have the means to produce the levels of Testosterone necessary to meet the needs of the male body. This condition is also referred to as Hypogonadism or Testosterone Deficiency. If Low-T occurs during adulthood as a result of aging, it is called Age-Related Hypogonadism or Somatopause.
There are many causes of Testosterone Deficiency, but all of these causes can be grouped into two categories: Primary Hypogonadism and Secondary Hypogonadism.
Primary Hypogonadism is any condition which directly affects the function of the testes and/or seminal vessicles.Secondary Hypogonadism is any condition which suppresses the release of Testosterone Precursor hormones (Luteinizing Hormone and Follicle Stimulating Hormone), which impedes normal Testosterone Production or fertility.
Causes of Low-T
Hypogonadism can be the result of a wide number of causes. Cancer, surgery, and trauma can impair physiological function. There are also some congenital defects which prevent the normal release of Testosterone or development of the male sex organs. The most common cause of Testosterone Deficiency is aging, though it can be exacerbated by other factors, such as sedentary lifestyle and obesity.
In children, Testosterone Deficiency leads to weaker bones, stunted growth, smaller muscles, and inhibited sexual potency. It can even have a major effect on personality development, as Testosterone is associated with many masculine traits such as confidence and assertiveness.
In adults, Low-T does not have effects which are immediately as noticeable, but they can still be significant and can strongly impact health, wellness, longevity, and fertility. Men with Low-T are more impacted by fatigue, low sex drive, loss of bone mineral density and strength, and increase in body fat than their peers. Beyond that, they are more likely to experience erectile dysfunction and cardiovascular complications such as heart disease and stroke.
Disorders and Conditions Associated with Testosterone Deficiency
Types of Congenital Testosterone Deficiency
Klinefelter Syndrome This is a genetic disorder in which the male is born with two X chromosomes. This leads to symptoms related to increased Estrogen Levels and inhibited Testosterone Production, including shrunken testes, breast development, feminine hair patterns, and infertility.
Kallmann's Syndrome Inability to produce Gonadotropin Releasing Hormone
Luteinizing Hormone Releasing Hormone Deficiency Insufficient production of the Testosterone Precursor Luteinizing Hormone.
Cryptochordism Partially-descended or undescended testicles.
Anorchism Completely undeveloped testes.
Causes of Acquired Testosterone Deficiency during Childhood and Adulthood
Testicular, Hypothalamic, and Pituitary Tumors
Radiation from Chemotherapy
Head Trauma or Testicular Trauma
Damage from Radiation
Damage from Chemotherapy
Symptoms of Aquired Testosterone Deficiency depend upon the age in which the symptoms appear. Childhood Hypogonadism is associated with late puberty or partial puberty, and can lead to symptoms of feminization such a gynecomastia and impaired hair development, as well as abnormally low muscle mass, increased body fat, and incomplete masculinization of the genitals.
How is Testosterone Produced?
The secretion of Testosterone by the testes and adrenal glands is the end-result of a a number of cyclical hormone interactions which originate and end at the brain. The delicate balancing act occurs on the Hypothalamic-Pituitary-Gonadal Axis. Upon stimulation, the Hypothalamus starts the process by releasing Gonadotropin-Releasing Hormone, which travels to the Anterior Pituitary Gland. Upon pituitary response by GnrH, Leuteinizing Hormone is released and flows through the blood stream to the adrenal glands and the testes. Upon reaching these target sites, LH interacts with Androgen Receptors in the Leydig Cells and this leads to Testosterone secretion.
All of these hormones are released in short bursts. In fact, the body doesn't produce much Testosterone, because Testosterone is such an incredibly potent Androgen. In a healthy male, it only takes four to seven milligrams of Testosterone to meet the functional needs of the body.
Onset of Testosterone Decline and Deficiency
Testosterone Levels after birth remain low until around the time puberty begins. Puberty is triggered by an increase in Testosterone, which increases rapidly and remains high through the teens and twenties. It isn't until the late twenties that Testosterone Production starts to fall into a state of slow and steady decline. By the time that a man reaches his eighties, free Testosterone Levels drop to as low as 20% of what they were in his twenties, and that's in the case of healthy men.
Adult-Onset Testosterone Deficiency can become symptomatic as early as the thirties in male patients with comorbid conditions such as diabetes combined with a sedentary activity level. In these cases, treatment can often be postponed and Testosterone Levels elevated simply by making healthy lifestyle changes, exercising, and losing weight. Men than smoke and drink are also more likely to experience Testosterone Deficiency, and at an earlier age.
Prevalence of Testosterone Deficiency
Low-T is very common in the United States and around the world. It may even be more common in America than most other countries because of the high incidence of obesity in our society. Researchers believe that around 13 million males in the country have symptomatic Low-T, but only around one in ten reach out to a professional for medical treatment. There is double the rate of Testosterone Deficiency among men with hypertension, diabetes, and obesity.
Partially because so few eligible men commonly reach out for treatment and partially because of the rapid increase in advertising and information about Low-T, Testosterone Therapy for Andropause is being prescribed more than ever, with few signs of slowing down in the coming years.
Adult males with Testosterone Deficiency are very likely to experience symptoms such as anxiety, depression, fatigue, loss of muscle mass, sexual dysfunction, and low libido. Furthermore, they are more likely to experience dangerous health conditions such as heart attack, cardiovascular disease, osteoporosis, stroke, and diabetes.
Research has shown that over two thirds of men with Low-T experience significant muscle fatigue. Around 1/3rd of men with Testosterone Deficiency have changes in bone mineral density which lead to increased risk of fractures and breaks.