Causes of Low Testosterone in Men, Symptoms and Treatment (Therapy)

Testosterone is a male sex hormone that controls the development of male sexual characteristics. Women also produce this hormone, but in small amounts. The levels of this hormone in a man’s blood can affect his mood, sex drive, muscle and bone mass as well. But what causes low testosterone in men?

What causes low testosterone in men?

Men can suffer from low testosterone levels at any age. The condition may occasion symptoms such as a much reduced sex drive, moodiness and even depression. There are two major causes of testosterone deficiency in men: primary hypogonadism and secondary hypogonadism. Other causes also exist.

1. Primary hypogonadism

Hypogonadism is a condition where sex glands produce insufficient or no sex hormones. In men, the gonads are the testes while in women, they are the ovaries. Primary hypogonadism, also called primary testicular failure is occasioned by a physical failure in the testes. The causes of primary hypogonadism include:

• Injury to the testicles that may impair the production of testosterone.
• Cancer treatments such as chemotherapy and radiation that can interfere with both sperm and testosterone production.
• Too much iron in the body, which can cause testicular failure.
• Long term testicular damage due to a mumps infection.
• Undescended testicles that can lead to low testosterone production in men.
• Some congenital disorders such as Klinefelter syndrome.

2. Secondary hypogonadism

“In secondary hypogonadism, the testicles are normal but function improperly due to a problem with the pituitary or hypothalamus.” [Mayo Clinic]. If drugs and illnesses affect the pituitary gland and lead to testosterone deficiency in men, then the condition that results is secondary hypogonadism. Here are the causes:

• Pituitary disorders such as tumors can cause hormone deficiencies. Other abnormalities of the gland can also impair the production and release of testosterone hormone in males.
• Radiation and surgical treatments of brain cancers and tumors located near the pituitary gland can also impair the pituitary gland and cause secondary hypogonadism.
• Obesity in males has been linked to low testosterone levels as well. According to a study published on Medscape, “Obesity, secondary (hypogonadotrophic) hypogonadism (SH), sleep disorders [such as obstructive sleep apnoea (OSA)] and type 2 diabetes mellitus (T2DM) in men have complex interlinks both with respect to mutual aetiopathogenesis as well as therapeutics. Correction of the attendant hypogonadism in obese men may serve to break this link and have beneficial effects beyond restoration of normal sexual function.”
• Inflammatory diseases such as tuberculosis, sarcoidosis and histiocytosis affect the pituitary gland and the hypothalamus. These can affect the production of testosterone and lead to testosterone deficiency in men.
• The effects of aging can also cause male hormone deficiency. As men age, their bodies produce less and less testosterone hormone. Therefore, older men tend to have lower testosterone levels than young ones.
• Some drugs and medications have also been found to affect the production of testosterone hormone. These may include some hormones as well as pain-relieving opiates.
• HIV/AIDS

Other factors that are likely to cause reduced testosterone include alcoholism and emotional stress.

Signs and symptoms of low testosterone levels in men

According to the FDA, Low T level in men is diagnosed when levels fall below a normal range (300- 1000 ng/dL. At this point, men may show some signs and symptoms as side effects of testosterone deficiency. The effects may relate and affect a man’s sex drive, hair growth rates, muscle mass, semen volumes, erections, mood, confidence etc.

In summary, here are the signs and symptoms of low testosterone in men:

1. Difficulty in getting an erection
2. Hair loss in men
3. Recurrent bouts of fatigue and reduced energy
4. Increasing body fat
5. Decreased bone bass
6. Reduced muscle mass
7. A low sex drive
8. Testosterone deficiency can also affect a man’s confidence.

The Urology Care Foundation notes that about 4 out of 10 men above the age of 45 suffer from testosterone deficiency and may show at least one or more of the symptoms above.

Low testosterone therapy and treatments

The effects of testosterone hormone deficiency can dim a man’s sex drive, motivation, confidence, energy, sex drive and eventually performance in bed. Treatment may involve the delivery of the male hormone through any one of the options. These include:

• Intramuscular shots such as gonadotropin injections
• Topical gels and patches
• Buccal patches
• Implanted pellets etc.

Not everyone is eligible for hormone replacement therapy. Your doctor can only recommend it if the levels of testosterone in your blood fall below the normal range.

Does low testosterone cause low sperm count?

Low testosterone in men does not cause low sperm count. Though testosterone is required for sperm production, the actual process is stimulated by other hormones.

Normally, “If sperm counts are very low, then blood testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) levels are also measured to the help determine the cause of infertility” [Hormone.org].

Sources and references

1. Medscape:
2. Hormone Health Network:
3. Mayo Clinic: