What Is Male hypogonadism?: Causes, Treatment, Symptoms and Complications

Male hypogonadism is the condition whereby a man’s gonads – or testicles – no longer produce physiological amounts of testosterone .
Testosterone is the main male sex hormone.

The presence of male hypogonadism may depend on a problem inherent in the testicles (in this case we speak of primary male hypogonadism) or on a problem at the level of the hypothalamic-pituitary axis, the axis that controls the activity of the testicles (secondary male hypogonadism ) .
Symptoms of male hypogonadismthey essentially consist in the lack of development of secondary sexual characteristics, a process which depends on testosterone.
Treatment of male hypogonadism varies depending on whether the hypogonadism present is primary or secondary.

Brief Review Of Hypogonadism And Gonadal Function

Hypogonadism is the medical term that indicates a more or less marked reduction in the functional activity of the gonads .

Testicles in men and ovaries in women, the gonads are the reproductive organs responsible for the production of sex cells or gametes and sex hormones
. Therefore, a reduction in the functional activity of the gonads leads to a decrease in the secretion of sex hormones , necessary for the development of secondary sexual characteristics and control of the reproductive system.

What Does The Activity Of The Gonads Depend On?

The activity of the gonads depends on the hypothalamus , a particular organ of the brain , and on the pituitary , a gland located at the base of the skull .
In fact, through the secretion of the so-called GnRH , the hypothalamus stimulates the pituitary gland to produce FSH and LH , two hormones which have, among other roles, the task of regulating the production of sex hormones by the gonads.

What Is Male Hypogonadism?

Male hypogonadism is the condition in which a man’s gonads (testes) no longer produce adequate amounts of testosterone , the primary male sex hormone.

Role Of Male Sex Hormones

The male sex hormones – testosterone in the lead – control the development of secondary sexual characteristics in men, i.e. the growth of the penis and testicles, the appearance of pubic, skin and beard hair , the strengthening of the muscles , the enlargement of shoulders and prostate enlargement .


Experts distinguish two types of male hypogonadism: primary male hypogonadism and secondary (or central) male hypogonadism .

  • Male hypogonadism is defined as primary when it results from a defect or problem located in the testicles.
    This means that the signals from the hypothalamus and pituitary are correct; what is not working properly are the reproductive organs that secrete sex hormones.
  • Male hypogonadism is said to be secondary when it results from defects in the hypothalamus or pituitary gland.
    This means that the testicles are healthy and would function properly if there weren’t an underlying problem in the hypothalamic and pituitary glands.


Possible causes of primary male hypogonadism include:

  • Klinefelter’s syndrome ;
  • Cryptorchidism , when not treated in childhood;
  • Some forms of post- mumps orchitis ;
  • Severe testicular trauma
  • Radiotherapy and/or chemotherapy treatment for testicular cancer .

Possible causes of secondary male hypogonadism include:

  • Kallmann’s syndrome ;
  • Diseases of the pituitary gland (eg: pituitary tumors );
  • Some inflammatory diseases , such as sarcoidosis , tuberculosis or histiocytosis, affecting the hypothalamus or pituitary gland, altering their activity;
  • AIDS _
  • Prolonged use of opioid pain relievers ( e.g. , codeine , morphine , oxycodone ,  methadone , fentanyl , hydromorphine, and didrocodeine);
  • Obesity ; _
  • Aging ; _
  • Hemochromatosis ; _
  • Nutritional deficiencies due to malnutrition ;
  • Brain surgery , which results in a more or less serious lesion of the hypothalamus ;
  • Brain tumors involving the hypothalamus;
  • Head injuries specifically affecting the hypothalamus or pituitary gland.

Symptoms And Complications

Symptoms and signs of male hypogonadism are numerous and vary with age.
During fetal life , the symptom pattern depends on how severe the testosterone deficiency is. From the most severe to the least severe, the clinical manifestations can range from: presence at birth of female genital organs → presence at birth of ambiguous genital organs → presence at birth of underdeveloped male genital organs.
At puberty , male hypogonadism is responsible for:

  • Reduced development of muscle mass
  • Failure to lower the tone of voice
  • No growth of body hair
  • Reduced development of penis and testicles
  • Excessive growth of the arms and legs, relative to the trunk
  • Abnormal breast development ( gynocomastia )

Finally, in adulthood , hypogonadism is a reason for:

  • Erectile dysfunction
  • Infertility
  • Reduced or absent beard growth, which is associated with the lack of hair on the rest of the body
  • Decreased muscle mass
  • Gynecomastia
  • Tendency to osteopenia or osteoporosis
  • Recurring sense of fatigue
  • Loss of libido
  • Hot flashes
  • Decline in concentration

When To See A Doctor?

A man should contact his doctor or a male reproductive specialist as soon as any symptoms of male hypogonadism appear.
Early diagnosis of the disorder has positive implications for treatment.


For a correct diagnosis of male hypogonadism, the following are essential: physical examination, medical history and hormone dosage tests on a blood sample .
If doctors suspect a disorder of the hypothalamus or pituitary gland, doctors may also need to do a CT scan or magnetic resonance imaging (MRI) of the head.

Hormon Dosage Tests

Hormone dosage tests on a blood sample typically include:

  • Measurement of FSH (or follicle stimulating hormone ) and LH (or luteinizing hormone ) levels;
  • Measurement of testosterone levels .


Treatment of male hypogonadism varies depending on whether the hypogonadism present is primary or secondary.
In cases of primary male hypogonadism, planning for adequate testosterone replacement therapy (or TRT ) is critical. TRT essentially consists of the exogenous administration of the main male sex hormone and is, in fact, a hormonal therapy.
In the case of secondary male hypogonadism, on the other hand, it is first of all important to treat or, at least, try to limit the disorder at the level of the hypothalamic-pituitary axis. In these situations, hormonal therapy with testosterone still has its usefulness, but it does not represent the first-line treatment, as instead occurs in primary type male hypogonadism.

Testosterone Replacement Therapy: Some Details

  • The administration of exogenous testosterone can take place: via a patch or a gel applicable to the skin ( transdermal route ), by injection ( parenteral route ) or via ingestible tablets ( oral route ).
  • Prolonged TRT increases the risk of cardiovascular disease , including heart attack and stroke . In this regard, in 2015, the FDA, i.e. the US government agency for the regulation of food and pharmaceutical products, required pharmaceutical companies, which trade exogenous testosterone, to report, in the package inserts (under the heading undesirable effects ) the increased risk of cardiovascular disease events.
  • Sometimes, in addition to TRT, clinicians may combine exogenous administration of GnRH (the hypothalamic hormone that stimulates the pituitary gland to secrete FSH and LH). GnRH is useful in cases of prepubertal patients (to promote puberty) and in cases of reduced sperm production .

Example Of Treatment Of Secondary Male Hypogonadism

When the cause of secondary male hypogonadism is a tumor of the hypothalamus or pituitary gland, the treatment options may include: surgery to remove the tumor, radiation and/or chemotherapy .


The Urology Care Foundation – an American foundation specializing in urology – argues that hypogonadism is a mostly chronic condition, requiring lifelong treatment.
The cases of secondary hypogonadism represent exceptions to what has just been stated, the causes of which can sometimes be treated with good results.

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