What Causes Low Testosterone? (Male Hypogonadism)

James Cunningham, BSc, CPT
Published by James Cunningham, BSc, CPT | Staff Writer & Senior Coach
Last updated: January 25, 2024
FACT CHECKED by Dr. Kristy Dayanan, BS, MD
Our content is meticulously researched and reviewed by an expert team of fact checkers and medical professionals. They ensure accuracy, relevance, and timeliness using the latest reputable sources, which are cited within the text and listed at the end of the article. Before publication and upon significant updates, we confirm factual accuracy, committed to providing readers with well-informed content. Learn more.

Men’s testosterone levels decrease about 1-2% every year, but this decline is expected after the age of 30.

However, if the testicles don’t produce enough testosterone, this condition is known as male hypogonadism. It can happen at any age and should be treated.

After hundreds of hours researching hypogonadism, drawing from both studies and my experience as a health and performance coach, I confirmed my findings with a urologist to ensure accuracy.

Read on to discover what causes low T and how you can treat it.

Quick Summary

  • To address low testosterone or male hypogonadism, it's essential to understand its causes, which can range from genetic factors to lifestyle influences.
  • Primary hypogonadism occurs when the testes don't produce sufficient testosterone, while secondary hypogonadism is due to issues with the hypothalamus or pituitary gland.
  • Low testosterone affects approximately 4 to 5 million men in the United States.
  • In my professional experience, adopting a proactive approach through lifestyle modifications and medical interventions like TRT can significantly improve testosterone levels and overall health.

What Is the Number One Cause of Low Testosterone?

man checking his crouch with a magnifying glas

The number one cause of low testosterone is not easy to determine, as different factors can bring about the condition.

You can develop hypogonadism if you experience an accident, illness, damage to the hypothalamus or the pituitary gland, or if you were born with certain medical conditions.

Between 19% and 35% of older men have hypogonadism, but it’s not just them who can experience it [1].

According to the Boston University School of Medicine, low T affects around 4 to 5 million men in the United States [2].

It can affect young men, children, and teenagers as well.

Common Causes of Hypogonadism

There are two main types: primary and secondary hypogonadism.

Let's dive into what causes them.

Primary Hypogonadism

ill woman and a man covering his crouch

Primary hypogonadism, or "primary testicular failure," occurs when the testes don't make enough testosterone. It could be genetic or due to an accident or illness.

Medical conditions that cause primary hypogonadism include:

Undescended testicles

Testicles form in the abdomen before birth and should move down to the scrotum. Sometimes they don't, which the Cleveland Clinic notes can fix itself [3].

But if not, it can cause testicle malfunction and lower testosterone.

Klinefelter Syndrome

Typically, males have one X and one Y chromosome. Klinefelter syndrome brings an extra X, leading to abnormal testicle development and reduced testosterone [4].


Excess iron in the blood can harm the testicles or pituitary gland, messing with testosterone levels.

Physical Injury to the Testicles

Injuring both testicles can slash testosterone production and lead to hypogonadism.

Mumps Orchitis

I recall a client whose mumps infection in adulthood led to impaired testicular function and reduced testosterone.

Cancer Treatment

Chemotherapy or radiation might hinder testosterone and sperm production. While usually temporary, the National Cancer Institute warns of potential permanent infertility [5].

Secondary Hypogonadism

aging man and a big stomach

Secondary hypogonadism stems from damage to the hypothalamus or pituitary gland in the brain, which governs testicular hormone production.

Medical conditions that cause secondary hypogonadism include:

Pituitary Disorders

A 2010 study published in the Journal of Pharmaceutical Technology and Research indicates that pituitary gland abnormalities can block hormone release to the testicles, reducing testosterone production [6].

Kallmann Syndrome

Abnormal hypothalamus function in Kallmann syndrome can cut down on testosterone production.

Inflammatory Diseases

Conditions like tuberculosis affect the pituitary gland and hypothalamus, lowering testosterone.


HIV/AIDS hits the hypothalamus, pituitary, and testes, dropping T levels.

Normal Aging

Aging can lead to late-onset hypogonadism, especially in men with type 2 diabetes or obesity, marked by a steady testosterone drop, as noted by the Cleveland Clinic [7].


My experience has taught me that significant weight gain is a common factor disrupting hormone production, including testosterone.


Opioids and steroids can mess with the pituitary and hypothalamus, impacting testosterone production, per a study in the Journal of Clinical Medicine [8].

Concurrent Illness

Severe stress from illness or surgery can temporarily shut down the reproductive system.

Symptoms of Testosterone Deficiency Syndrome

shirtless man holding his chest and a man upset

Hypogonadism symptoms vary with age, emerging during fetal development, puberty, or adulthood.

If the body doesn’t produce enough testosterone during fetal development, it may result in the impaired growth of external sexual organs:

  • Underdeveloped male genitals
  • Female genitals
  • Ambiguous genitals (neither male nor female)

If hypogonadism happens during puberty, it can hamper average growth and cause problems with:

  • Voice deepening
  • Muscle development
  • Growth of body and facial hair
  • Development of the penis and testicles
  • Enlarged breasts (gynecomastia)
  • Overly long limbs

Hypogonadism in adult males can affect specific masculine physical characteristics and hinder normal reproductive function.

Early signs and symptoms to look out for might include:

  • Low-sex drive
  • Low energy levels
  • Depression
  • Bad mood, memory, and cognitive functions

How Do You Fix Low Testosterone?

healthy men flexing muscles

You can fix low testosterone levels by making specific lifestyle changes or undergoing testosterone replacement therapy.

Lifestyle Changes

In my practice, I've guided many clients to increase physical activity and optimize their diet, significantly improving their testosterone levels.

Also if your condition doesn't require medical intervention, you can opt for some high-quality testosterone boosters to naturally ramp up your body's hormone production.

Testosterone Replacement Therapy (TRT)

Based on my experience working alongside medical professionals, TRT is a common prescription for male hypogonadism.

“Treatment can consist of different formulations of testosterone, including topical gels or patches, injections into the muscle or skin, nasal gels, long-acting pellet implants, and other options.”

- Sriram Eleswarapu, MD, Ph.D., Urology Specialist 

TRT tackles low T symptoms like low libido, muscle mass, and energy. It aids teenagers in normal masculine development.

However, TRT methods like transdermal applications and injections have side effects that need careful consideration.

man with acne and another man covering his crouch

TRT's potential side effects are:

  • Breast enlargement or tenderness
  • Acne
  • Skin irritation 
  • Sleep apnea
  • Swelling in the ankles caused by fluid retention
  • Smaller testicles
  • Difficulty urinating
  • Decreased sperm count

Notably, TRT isn't for everyone, especially men with early prostate cancer, due to concerns that testosterone might spur cancer growth [9].

That's why anyone considering this treatment plan is recommended to undergo prostate screening first.


Does Sleep Apnea Cause Low Testosterone?

Yes, sleep apnea can cause low testosterone, since most daily testosterone production occurs during sleep. Studies have proven that both the duration and quality of sleep influence testosterone levels.

Can Low Testosterone Cause Joint Pain?

Yes, low testosterone can cause joint pain. Low levels of this hormone can directly contribute to joint pain and arthritis and indirectly through weight gain, which can further impact bone cartilage and joint health.


  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2948422/
  2. https://www.bumc.bu.edu/sexualmedicine/publications/prevalence-diagnosis-and-treatment-of-hypogonadism-in-primary-care-practice/
  3. https://my.clevelandclinic.org/health/diseases/17594-undescended-testicles
  4. https://my.clevelandclinic.org/health/body/23964-testicles
  5. https://www.cancer.gov/about-cancer/treatment/side-effects/fertility-men
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3255409/
  7. https://my.clevelandclinic.org/health/diseases/15603-low-testosterone-male-hypogonadism
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6571549/
  9. https://www.hopkinsmedicine.org/news/articles/2018/05/testosterone-as-a-drug
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About The Author

James Cunningham, BSc, CPT
Staff Writer & Senior Coach
James Cunningham, BSc, CPT holds a BSc degree in Sport & Exercise Science from University of Hertfordshire. He's a Health & Performance Coach from London that brings a unique blend of academic knowledge of health supplements and practical exercise experience to the table for his readers.
Learn more about our editorial policy
Dr. Kristy June Dayanan, BS, MD is an author with a BS degree from University of the Philippines and an MD from University of Perpetual Help System. Her ability to simplify medical science complexities and dietary supplement jargon for the average reader makes her a valued medical fact checker and reviewer.
Learn more about our editorial policy
Dr. Harshi Dhingra, MBBS, MD is a published peer-reviewed author and renowned physician from India with over a decade of experience. With her MBBS from Bharati Vidyapeeth and an MD from Rajiv Gandhi University, she actively ensures the accuracy of online dietary supplement and medical information by reviewing and fact-checking health publications.
Learn more about our editorial policy

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