Low Testosterone Symptoms and Diagnoses


  • Testosterone and its function in the body
  • Testosterone production and secretion
  • Physical symptoms related to low testosterone
  • Conditions that could cause low testosterone
  • Diagnosing low testosterone levels in men

Testosterone and Its Function

Testosterone is the most important male sex hormone, also known as androgen, produced in the male body. It is the hormone that is primarily responsible for producing the typical adult male attributes and characteristics. At puberty, testosterone stimulates the physical changes that characterize the adult male, such as enlargement of the penis and testes, growth of facial and pubic hair, deepening of the voice, an increase in muscle mass and strength, Adam’s apple, bigger bones and growth in height. Below we discuss Low Testosterone Symptoms and proper diagnoses.

Testosterone is the hormone of sexual desire. Throughout adulthood, testosterone helps stimulate and maintain sex drive, the production of sperm cells, male hair patterns, muscle mass, proper fat distribution and bone density.

Testosterone is produced in the testes and in adrenal glands. While testosterone is the main male sex hormone, women also produce testosterone in small quantities. In women, very small amounts of testosterone are produced by the ovaries, about 2o times less than men.

Testosterone is a major factor in prepubescent male development, and is active long before puberty begins. For example, while a fetus is still in the womb, testosterone and a related substance cause the male genitalia to form.

Testosterone Production

Testosterone secretion. The body controls the production of testosterone through what is called a “negative-feedback loop”. Chemical hormone signals from two glands in the brain, the pituitary and hypothalamus  tell the testes when and how much testosterone to produce.

Testosterone stimulating hormones. The hypothalamus controls hormone production in the pituitary gland by means of gonadotropin-releasing hormone (GnRH). This hormone tells the pituitary gland to make follicle-stimulating hormone (FSH) and luteinizing hormone (LH). LH signals the testes to produce testosterone when not enough is circulating in the body.

Maintaining normal androgen levels. When the testes begin producing too much testosterone, the brain sends signals to the pituitary to make less LH, which in turn stops signaling the specializes cells in the testes called Leydig cell to secrete testosterone.

This hormone feedback signaling slows the production of testosterone so the body secretes just the right amount it needs. If the testes secrete too little testosterone, the brain will start sending signals to the pituitary gland telling it to start secreting more LH, which then signals the testes to make more testosterone.

Low Testosterone Symptoms and Diagnoses. ED Therapy for Men with Male Impotence Symptoms

Physical Symptoms Related to Low Testosterone

Signs and symptoms of low testosterone in men can include low sex drive, ED erectile dysfunction symptoms such as weak or less frequent erections, excessive weight gain, extreme fatigue and feeling tired all the time, lowered sperm count, infertility, or increased breast size. Men with andropausal symptoms also tend have symptoms similar to those seen during menopause in women such as mood swings, depression, hot flashes, bursts of anger and increased irritability, inability to focus or concentrate, social withdrawal, insomnia and depression.

Some of the main testosterone symptoms men notice are:

  • Low sex drive
  • Feeling tired all day
  • Reduced sperm production
  • Loss of muscle mass
  • Low energy levels
  • Improper fat distribution
  • Excessive weight gain
  • Sadness or depression
  • Loss of motivation, drive and enthusiasm
  • Bursts of anger and wide mood swings
  • Inability to focus or concentrate well
  • Loss of bone density (Osteoporosis)
  • Reduced red blood cell production

 Androgen Deficiency

Some men with very Low T may have a prolonged and severe decrease in testosterone production also known as Hypogonadism or Low T. As a result, they may experience loss of body hair and much reduced muscle mass, with osteoporosis their bones may be more brittle and prone to fracture, and their testes may shrink and become smaller and softer. In younger men, low testosterone production may reduce the development of body and facial hair, muscle and bone mass, and genitals. In addition, their voices also may fail to deepen.

Health Conditions That Could Cause Low Testosterone

  • The effects of aging on testosterone production – Andropause
  • Testes-Based Conditions including malfunction of the Leydig cells
  • Pituitary/Hypothalamus-Based Conditions
  • Genetically-Based Conditions

There are a number of specific medical conditions that can cause low testosterone. Often, such conditions are most evident in younger men. Some of these conditions are associated with the testes, pituitary gland and hypothalamus gland. Other men experience low testosterone levels as a result of various genetic factors.

The effects of Aging on testosterone production – Andropause

As men age, their ability to produce testosterone naturally declines. Some men’s production of LH decreases with aging, which lowers the hormone needed to signal increased testosterone production. Moreover, as men age a protein called sex hormone binding globulin (SHBG) increases in older men, which further reduces the amount of free (bio-available and unbound androgen) testosterone in the blood that is available to tissues, such as muscles. Read more about Free Testosterone vs Total Testosterone.

Aging in men also causes changes in the daily cycle of testosterone production. For example, younger men show a peak of testosterone in the morning, but this finding is blunted in older men and occurs with a lack of spontaneous or morning erections one sees in the youthful years.

The decline in testosterone production as men age is sometimes referred to as Andropause, or male menopause.

Testes-Based Health Conditions

Men whose testosterone deficiency is caused by a malfunction or an abnormality in the testes often display increased FSH levels, increased LH levels and impaired sperm production which can cause fertility problems in men. These adverse medical conditions include:

  • Trauma – a direct physical injury to the testes may damage the cells that produce testosterone.
  • Orchitis – testicular inflammation can occur after a post-puberty bout with the mumps where there is a higher risk of risk of infertility than low testosterone.
  • Radiation treatment or chemotherapy – these therapies for other diseases may damage the specialized testosterone-producing Leydig cells of the testes.
  • Testicular tumors – treatment of testicular tumors may directly affect testosterone production.

Pituitary/Hypothalamus-Based Health Conditions

Men whose low testosterone levels result from defects in the pituitary or hypothalamus generally have a low or low-normal FSH level and low or low-normal levels of LH. These conditions include:

  • Pituitary tumors – the growth of abnormal tissue in the pituitary can disrupt the gland’s normal functioning and interfere with hormone production.
  • HIV/AIDS – viruses or other infectious agents may directly or indirectly affect the hypothalmus, pituitary or testes and can decrease testosterone levels; as many as 50 percent of men infected with the human immunodeficiency virus (HIV) may have low testosterone.

Genetically-Based Health Conditions

Men may have low testosterone as a result of chromosomal abnormalities or genetically-based conditions. These conditions include:

  • Klinefelter’s syndrome – a genetic condition in which an extra X chromosome is present (about one in every 400 men have this); testosterone production is low to low normal; men with this syndrome also may have markedly reduced bone density.
  • Kallmann’s syndrome – usually a recessive genetic disorder associated with the X chromosome, which occurs in about one of every 10,000 men. A deficiency of GnRH impairs the release of LH and FSH, which decreases testosterone production; men with the syndrome lack the sense of smell; testes do not enlarge at puberty.
  • Prader-Willi syndrome – a genetic disorder characterized by decreased muscle tone in infancy that improves with age, underdeveloped genitals (including undescended testes in boys) and low sex hormone levels. An obsession with food and compulsive eating, also linked with this disorder, may begin before the age of six.
  • Myotonic dystrophy – the most common adult form of muscular dystrophy, this genetic condition only occurs in men and is carried on the Y chromosome; because testicular failure usually occurs around the age of 30 to 40, men may have sons at risk for the disease.

Diagnosing Low Testosterone

  • Medical and family history
  • Physical examination
  • Measuring hormone levels
  • Other hormone tests

Your medical history is important in properly diagnosing Low T.

Sometimes physical symptoms can suggest a medical problem. For example, a man who, as he ages, has a progressive decrease in muscle mass, loss of libido, erectile dysfunction (ED) or reduced sperm count may have low testosterone.

Similarly, a teenager who still has the appearance of a young boy – small testes, penis and prostate; scant pubic and body hair; and a high-pitched voice – shows clear signs of someone with inadequate testicular function.

There are cases, though, that may involve some medical detective work. Therefore, it is extremely important to provide the doctor with a detailed medical history. Things that should be discussed include:

  • past or present major illnesses;
  • all prescription and nonprescription drugs currently being taken;
  • family/relationship problems, such as sexual problems; and
  • any major life events or changes that have occurred.

A family history also may help the doctor to pinpoint a genetic basis for the problem. Your hormone doctor can use these clues to identify the correct diagnosis before prescribing Testosterone Replacement Therapy.

Physical Examination

During the physical examination, the doctor will look at:

  • the amount and distribution of body hair;
  • presence and degree of breast enlargement;
  • size and consistency of the testes;
  • abnormalities in the scrotum; and
  • size of the penis.

Measuring Hormone Levels

Testosterone levels vary from hour to hour, so the time at which blood is drawn for testing can affect the results. However, the generally acceptable range of values is 300 to 1,200 nanograms per deciliter (ng/dl). Generally, the highest testosterone levels occur in the early morning hours; therefore, doctors will often measure testosterone levels at this time and on an empty stomach.

FREE Testosterone vs Bioavailable Testosterone vs Bound Testosterone

Testosterone circulates in the blood in three forms:

  • Bound Testosterone – about 30 percent of testosterone is bound tightly to a protein called sex hormone binding globulin (SHBG);
  • Bioavailable Testosterone – about 68 percent is weakly bound to another protein called albumin but can over time become bioactive in the body; and
  • Free Testosterone – about two percent circulates freely in the bloodstream.
  • When diagnosing Low T, the most important measure of androgen in a man’s blood is Free Testosterone which is entirely bio-available for use by the body.

Determination of low testosterone may require more than one blood test. A normal total testosterone reading may not necessarily indicate that a man has normal levels of free testosterone. For example, some men with increased levels of SHBG and low blood levels of free testosterone may have normal levels of total testosterone. Therefore, labs often measure the total testosterone levels and its components in a testosterone serum lab test. Read more about testosterone serum lab testing.

Other hormone tests for low testosterone symptoms

  • Because low testosterone levels may affect bone mass, the doctor may want to assess any bone loss with bone density testing to see if Osteoporosis is present.
  • Genetic testing can confirm the presence of an inherited condition.
  • If tests cause the doctor to suspect a problem within the pituitary gland, he/she may want to examine the gland to see if a tumor is present. Two examination procedures are most common, and neither penetrates the skin. A computed tomography, or CT, is a computer-assisted X-ray process. Magnetic resonance imaging, or MRI, uses a combination of radio waves, high intensity magnetic fields and computer technology to produce images of the body’s interior.
  • HGH Human Growth Hormone Level testing. Many men who are low in testosterone are also low in Human Growth Hormone. HGH works very closely with testosterone to help maintain and repair the body’s tissues, creating sexual desire and arousal, sperm potency and prolonging firm erections in men.