Testosterone & Hypogonadism

Hypogonadism (Low Testosterone): The Complete Guide


Joe McLean, BSc, MRes
March 17, 2024
Take-home points:
  • Hypogonadism is a condition where clinically low testosterone levels have been diagnosed, along with symptoms associated with the deficiency.
  • Symptoms include low sex drive, erectile dysfunction, fatigue, and depression.
  • Hypogonadism is a treatable condition through testosterone replacement therapy, which restores testosterone levels within the normal range.
  • If you suspect you have hypogonadism, it's important to visit your healthcare professional.

What is hypogonadism?

Hypogonadism is a condition that affects men when the body does not produce an adequate amount of testosterone, a vital hormone for maintaining overall health. This condition is prevalent among men, and numerous treatment options are readily accessible to alleviate symptoms.

The role of testosterone in men

Testosterone is widely recognised as the primary male sex hormone, but it has many roles in the body. Alongside its role in regulating body fat and muscle mass, testosterone also plays a pivotal part in:1

  • The production of red blood cells.
  • Cognitive function.
  • Development of male sexual organs, such as the testes (testicles).
  • Male puberty, facilitating the growth of body and facial hair as well as the deepening of the male voice.

Starting around the age of 40, testosterone levels typically begin to decline gradually. In certain cases, these levels can drop to clinically low points, resulting in a range of symptoms that can significantly impact a man's overall quality of life.2,3

Learn more about how hypogonadism is diagnosed

Hypogonadism (low testosterone) symptoms in men

Hypogonadism is linked to various conditions, including type 2 diabetes, cardiovascular disease, and obesity.2 It often presents itself through symptoms like low sex drive (low libido), erectile dysfunction, feelings of depression, and irritability. Additionally, it's associated with anemia, reduced muscle mass, and decreased bone density, which can result in overall weakness, limited mobility, and an elevated risk of falls and fractures.4

Signs and symptoms of Hypogonadism

Hypogonadism can also cause strain on relationships with partners, particularly when undiagnosed and neither part of the couple understands the underlying cause for these changes. Therefore, it is crucial that hypogonadal men are diagnosed and treated appropriately to ensure their continued quality of life into older age.  

Prevalence of low testosterone  

Hypogonadism is a common condition in men. In fact, approximately 6% of middle-aged men are hypogonadal, and the prevalence tends to increase with age. Indeed, men in their seventies produce 35% less testosterone than younger men.5

Primary and secondary hypogonadism  

There are two types of hypogonadism which are classed by the specific cause of the testosterone deficiency.  

Primary hypogonadism

In primary hypogonadism, the deficiency originates from issues within the testes. There are many potential reasons for this, including:3

  • Normal ageing.
  • Cancer treatment.  
  • Injury to the testicles.  
  • Some genetic conditions, such as Klinefelter syndrome.
Secondary hypogonadism

Secondary hypogonadism differs in that the testes operate normally, and the underlying cause of the condition lies in the improper functioning of the pituitary gland or the hypothalamus, both of which are key brain structures responsible for regulating testosterone production. Conditions that may lead to secondary hypogonadism include:3

  • Inflammatory diseases.
  • Infections such as HIV.
  • Certain medications, particularly those which are opiate-based.  
  • Obesity.  
  • Excessive stress. 

Hypogonadism can have various underlying causes, and while some of them, as discussed here, may be linked to serious health conditions, it's important to note that in many cases, if you're an older man experiencing hypogonadism symptoms, age-related factors may be contributing to the condition. Nonetheless, it's crucial to consult with a healthcare professional who can confirm this through appropriate tests.

Diagnosis and treatment of hypogonadism

If you're diagnosed with hypogonadism, there is positive news—it's a treatable condition through testosterone-based therapies, commonly referred to as testosterone replacement therapy. These therapies are designed to elevate testosterone levels in the bloodstream and provide relief from your symptoms. Diagnosis typically involves evaluating the clinical symptoms of hypogonadism and conducting two blood tests to confirm testosterone deficiency. Additional tests may be performed to pinpoint the underlying cause of your condition.1

Learn more about how to understand your testosterone test results

Certain patients are advised against the prescription of testosterone replacement therapy. This group includes individuals with a history of male breast cancer, prostate cancer, or heart failure, as well as those with a high concentration of red blood cells in their blood (high hematocrit). Additionally, individuals who are actively attempting to conceive a child should also avoid this therapy. It is crucial to consult with a healthcare professional to determine the most appropriate treatment plan based on individual health circumstances.1

Which doctor treats hypogonadism?

Hypogonadism is a hormonal condition. If you have concerns about your testosterone levels, your first point of contact is often a general practitioner or nurse. If they suspect you have hypogonadism, you may be referred to an endocrinologist who specialises in treating hormone related conditions.

Hypogonadism (low testosterone) treatment in men

Testosterone replacement therapy is typically consisdered for the management of hypogonadism. There are different types testosterone replacement therapies available, each with distinct methods of administration. These options include oral treatments, nasal sprays applied to the nostrils, intramuscular injections administered into the arm or leg, and gels applied to the skin for absorption into the bloodstream. You should consult with your healthcare professional to identify the most suitable option for you.

Visit our article on hypogonadism treatment options to learn more

If in doubt, speak to a specialist

If you are concerned that you may have hypogonadism, it's important to schedule an appointment with your healthcare professional. They can conduct a thorough evaluation of your symptoms, provide a professional diagnosis, and initiate discussions with you on the most appropriate steps to effectively manage your symptoms.

Continue the conversation on the TRTed Community!


  1. ​​EAU Guidelines. Edn. presented at the EAU Annual Congress Barcelona 2019. ISBN 978-94-92671-04-2.
  2. Goodale T, et al. Methodist Debakey Cardiovasc J 2017;13(2):68-72.
  3. Kumar P, et al. J Adv Pharm Technol Res. 2010; 1(3): 297-301.
  4. Barbonetti A. Andrology 2020; 8(6):1551-1566.
  5. McBride, et al. Asian J Androl 2015; 17(2): 177-186.

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