Sven Wombwell
Article by: Sven Wombwell
Estimated 7 minutes read

Testosterone, the primary male sex hormone, is crucial in maintaining muscle mass, bone density, mood regulation, and sexual function. However, as men age, there is a natural decline in testosterone levels. Therefore, It's no wonder that many men worry about low testosterone (Low T), but is low testosterone genetic? While various factors contribute to low T levels, the influence of genetics remains a subject of growing interest.

Studies show there is a strong inherited link with serum testosterone, with genetic factors accounting for 40-70% of the variation in testosterone levels in men (Travison et al. 2014) and 65% in women (Hong et al. (2001)

In this article, we'll look into the fascinating world of testosterone and genetics. We'll explore the genetic components of low testosterone and how lifestyle and environmental factors affect genes. We'll also consider whether genetic factors are to blame for the growing number of men with low T. 

Understanding Testosterone and Its Role

Before diving into genetics and low testosterone, we must understand the hormone itself. Testosterone is responsible for a wide range of functions in the male body, including:

  • Bone Density: Testosterone is crucial for maintaining healthy bone density. Reduced testosterone levels can lead to weaker bones, making them more prone to fractures.
  • Mood Regulation: Testosterone influences mood and mental well-being. Low testosterone levels can cause depression and mood swings.
  • Sexual Function: Testosterone is crucial for sexual function. It plays a key role in libido, erectile function, and overall sexual pleasure.
  • Red Blood Cell Production: Testosterone promotes red blood cell production, helping maintain optimal oxygen levels in the body.
  • Distribution of Fat: Testosterone influences fat distribution, helping to keep body fat in check. Low testosterone levels can increase body fat, particularly visceral fat around the abdomen.

Now we know what testosterone does. Let's explore if genetics can influence testosterone levels.

The Genetic Component of Low Testosterone

Some men may inherit genetic variations that increase the risk of low T. These genetic factors can affect testosterone production, transportation, or response to testosterone. It's like a code written into their DNA that impacts hormone production.

For instance, specific gene variants can interfere with the hypothalamus and pituitary function. These areas of the brain control testosterone production. If genes mutate and affect this control system, the result could be low testosterone levels.

The Impact of Environmental and Lifestyle Factors

While genetics play a role, they are just one piece of the puzzle. Environmental and lifestyle factors also considerably influence testosterone levels, such as:

1. Diet: Poor nutrition, too much sugar and processed foods can lead to obesity, significantly reducing testosterone. A balanced diet with essential nutrients, healthy fats, and proteins supports testosterone production.

2. Physical Activity: Regular exercise, particularly resistance training, helps maintain healthy testosterone levels. In contrast, a sedentary lifestyle can contribute to low testosterone.

3. Stress: Chronic stress can lead to high cortisol levels, a hormone that affects testosterone and sleep quality. Effective stress management techniques are crucial to combat this imbalance.

4. Obesity: Excess body fat, especially abdominal (visceral) fat, can convert testosterone into estrogen. This conversion lowers testosterone levels, creating a cycle that makes it difficult to lose weight. Obesity is also a primary risk factor for type 2 diabetes.

5. Endocrine-Disrupting Chemicals: Certain chemicals in products like plastic water bottles, such as bisphenol A (BPA) and phthalates, reduce testosterone levels. Research shows these chemicals also enter the wider environment and contribute to low testosterone levels. A notable study from 2007 revealed a worrying trend. Gen Z and millennial men have lower testosterone levels than previous generations. The average testosterone level has fallen by around 1 percent yearly.

In 1987, a study conducted in Massachusetts found that the typical testosterone level for a 60-year-old man was approximately 500ng/dL [5]. However, fast forward to 2002, and the testosterone level of a 60-year-old man had fallen to around 435ng/dL.

This data suggests that, on average, testosterone levels in men have been falling at a rate of around 1% per year, more or less.

The Evolving Landscape of Testosterone Levels

Recent research has shed light on the changing landscape of testosterone levels. Between 1996 and 2016, studies have shown a decline in testosterone levels among adolescents and young men. 10-40 percent of adult males had a testosterone deficiency. When evaluating testosterone levels, these findings highlight the need to consider environmental factors, including childhood conditions, stress, and socioeconomic status.

Low Testosterone and Genetic Disorders

Certain genetic disorders can lead to low testosterone levels. 

These conditions include:

1. Klinefelter Syndrome: This genetic disorder is when a man has one or more extra X chromosomes. It typically remains undiagnosed until adulthood and can result in smaller testes and low testosterone production. The condition can cause reduced muscle mass, body and facial hair, and enlarged breast tissue. 

The effects of Klinefelter syndrome vary, and not everyone has the same signs and symptoms. Treatment is usually lifelong TRT medication.

2. Kallman Syndrome: A rare genetic condition characterized by a lack of certain hormones responsible for sexual development. It can cause delayed or absent puberty, poor sense of smell, and lower testosterone levels. Men born with this condition often have underdeveloped testes and erectile dysfunction and may be infertile. Hormone replacement therapy is a standard treatment.

3. Prader-Willi Syndrome: This genetic condition results from a chromosome 15 defect impacting hypothalamus function. Symptoms include issues with hunger, growth, sexual development (such as micropenis and undescended testicles), temperature regulation, mood, and sleep. While there is no cure, testosterone replacement therapy can restore sex hormone levels.

The Genetics of SHBG  

Apart from the above genetic conditions, the sex hormone-binding globulin (SHBG) gene is fascinating. SHBG binds to testosterone, regulating its availability to body tissues. Mutations in the SHBG gene can significantly influence testosterone levels. 

In a 2011 study, researchers examined the SHBG genes of 14,000 men. Ultimately, they found those with multiple variations in the SHBG gene were 6.5 times more likely to have reduced testosterone levels. A 2021 study further supported these associations between SHBG gene variations and hypogonadism.

The Role of Testosterone Replacement Therapy (TRT)

Testosterone replacement therapy (TRT) is an effective treatment option for men with low T. TRT involves supplementing testosterone to restore optimal levels. A plan should include lifestyle changes, hormones, other medications and supplements. These changes will help you balance your hormones and improve your overall well-being.

Many medical providers have no training in TRT, so it is crucial to choose one who knows what they are doing. Assessments should involve a full symptoms review and blood test. If you have symptoms of low T, but your provider says your levels are normal, you still might benefit from therapy. In cases like this, they will not offer you help. 

Male Excel clinics are experts in identifying low testosterone symptoms. We offer life-changing healthcare that many doctors can't provide due to restrictions from insurance companies. 

In Conclusion: Is Low Testosterone Genetic

To answer the question, "Is low T genetic?" it's crucial to recognize the complex nature of this condition. While genetic factors can play a role in testosterone regulation, they are just one piece of the puzzle. TRT, lifestyle and environmental factors all contribute to long-term health.

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1. Thomas G. Travison, Andre B. Araujo, Amy B. O’Donnell, Varant Kupelian, John B. McKinlay. "A Population-Level Decline in Serum Testosterone Levels in American Men." The Journal of Clinical Endocrinology & Metabolism, Volume 92, Issue 1, January 2007.
2. Patel P, Fantus R, Lokeshwar S, et al. "Trends in Serum Testosterone Levels Among Adolescent and Young Adults Men in the United States." Presented at: 2020 AUA Virtual Experience; May 15, 2020.
3. Ohlsson C, et al. "Genetic determinants of serum testosterone concentrations in men." PLoS Genet. 2011 Oct;7(10):e1002313.
4. Magid, K., Chatterton, R.T., Ahamed, F.U. et al. "Childhood ecology influences salivary testosterone, pubertal age and stature of Bangladeshi UK migrant men." Nat Ecol Evol 2, 1146–1154, 2018.
5. Population-Level Decline in Serum Testosterone Levels in American Men | The Journal of Clinical Endocrinology & Metabolism | Oxford Academic [Internet]. [cited 2022 Nov 21]. Available from:
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