WHAT CAUSES LOW TESTOSTERONE?

Low testosterone is a common health concern that affects men of all ages. While testosterone naturally declines over time, there are many other factors that can contribute to lower levels, including lifestyle habits, medical conditions, medications, and problems affecting the testes or hormone producing glands.

Understanding the cause of low testosterone is important because treatment depends on why levels have fallen in the first place. In some cases, improving sleep, losing weight, or managing an underlying health condition may help testosterone levels recover naturally. In other situations, further medical assessment or treatment may be needed.

If you are experiencing symptoms such as fatigue, reduced sex drive, mood changes, or difficulty building muscle, a Testosterone Blood Test can help determine whether low testosterone may be contributing to your symptoms.

There is no single cause of low testosterone.

Testosterone levels can be affected by ageing, obesity, chronic illness, poor sleep, stress, medication use, alcohol consumption, and conditions affecting the testes or hormone signalling pathways. In some cases, testosterone levels may temporarily fall during illness and recover once health improves. In others, levels remain low due to an ongoing medical condition or hormonal problem.

Because there are many possible causes, identifying the underlying reason is one of the most important steps in determining the most appropriate treatment approach.

One of the most common causes of low testosterone is the natural ageing process.

Testosterone levels typically begin to decline gradually from around the age of 30. On average, levels may fall by around 1% per year, although this varies significantly between individuals. Some men maintain healthy testosterone levels well into later life, while others experience a more noticeable decline.

Importantly, ageing does not automatically mean a man will develop clinically low testosterone.

Some men may have lower testosterone levels without experiencing any symptoms, while others develop symptoms despite having testosterone levels that still fall within the normal laboratory range.

Healthcare professionals sometimes use a screening tool called the ADAM questionnaire (Androgen Deficiency in the Aging Male) to assess symptoms commonly associated with testosterone deficiency, including low libido, low mood, fatigue, and reduced energy levels.

Obesity is strongly linked to low testosterone levels and is one of the most common contributing factors seen in clinical practice.

Body fat is not simply an energy store. It is hormonally active tissue that can influence how testosterone is produced and regulated. Fat cells can convert testosterone into oestrogen, reducing the amount of available testosterone in the body. Obesity is also associated with increased inflammation and lower levels of sex hormone binding globulin (SHBG), which can further affect hormone balance.

Abdominal fat appears to have a particularly strong impact because it is more metabolically active than fat stored elsewhere in the body.

There is also a self perpetuating cycle between obesity and testosterone. Low testosterone may contribute to reduced motivation, lower activity levels, and loss of muscle mass, making weight gain more likely. As body fat increases, testosterone levels may fall further, creating an ongoing cycle that can be difficult to break.

The good news is that weight loss may help improve testosterone levels in some men, particularly when combined with regular exercise and dietary improvements.

Chronic stress can have a significant impact on testosterone production.

When the body experiences prolonged stress, it produces increased amounts of cortisol, often referred to as the stress hormone. Persistently high cortisol levels can suppress the hypothalamic pituitary gonadal axis, which plays a central role in regulating testosterone production.

Stress can also contribute indirectly to lower testosterone by affecting other aspects of health. People under chronic stress are often more likely to experience:

• Poor sleep

• Reduced physical activity

• Weight gain

• Unhealthy eating habits

All of these factors can further contribute to lower testosterone levels.

Managing stress through exercise, mindfulness, social connection, and healthy routines may help support both hormonal and overall health.

Sleep is one of the most important factors influencing testosterone production.

Much of the body's testosterone production occurs during sleep, which is why testosterone levels are typically highest in the early morning. Poor sleep quality or insufficient sleep can therefore reduce testosterone production over time.

Several sleep related issues may contribute to lower testosterone levels, including:

• Sleep deprivation

• Shift work

• Sleep apnoea

• Frequent night waking

• Poor sleep quality

Research has shown that men who consistently get inadequate sleep may experience measurable reductions in testosterone levels.

Improving sleep habits may therefore be one of the most effective natural ways to support healthy hormone levels.

Many long term health conditions can affect testosterone production.

Type 2 diabetes and obesity are among the most common medical conditions associated with low testosterone. However, other conditions may also contribute, including:

• Kidney disease

• Liver disease

• Metabolic syndrome

• Chronic inflammatory conditions

• Long term illnesses

These conditions may interfere with hormone production, hormone signalling, or the body's ability to regulate testosterone normally.

The encouraging news is that improving or treating the underlying condition may sometimes allow testosterone levels to recover naturally.

Because symptoms often overlap with other health issues, proper medical assessment is important before drawing conclusions.

Hypogonadism is the medical term used to describe low testosterone.

Primary hypogonadism occurs when there is a problem directly affecting the testes, preventing them from producing adequate testosterone.

Possible causes include:

• Klinefelter syndrome

• Testicular injury

• Previous surgery

• Mumps related testicular damage

• Autoimmune conditions

• Haemochromatosis

• Chemotherapy or radiotherapy

In these situations, testosterone production may be directly impaired because the cells responsible for producing the hormone have been damaged.

Some causes are obvious, while others require specialist investigation to identify.

Certain medications can contribute to lower testosterone levels.

Some of the most commonly associated medications include:

• Opioid pain medications

• Antipsychotic medications

• Certain antidepressants

• Long term corticosteroids such as prednisolone

• Some blood pressure medications

These medications may affect hormone production through different mechanisms, including suppression of hormone signalling pathways in the brain.

If you suspect medication may be affecting your testosterone levels, it is important not to stop treatment without first speaking to your healthcare provider.

A medication review may help determine whether alternatives are available.

Lifestyle factors play a major role in testosterone production.

Excessive alcohol consumption can lower testosterone levels through several mechanisms. Alcohol may directly damage Leydig cells in the testes, which are responsible for producing testosterone. Heavy alcohol intake can also affect hormone signalling pathways and liver function.

Physical inactivity may also contribute to lower testosterone levels. Regular exercise, particularly resistance training and high intensity exercise, is associated with healthier testosterone production.

Smoking and recreational drug use, including marijuana, may also negatively affect hormone levels in some individuals.

For many men, lifestyle improvements can make a meaningful difference to testosterone levels without the need for medication.

Low testosterone can cause a wide range of symptoms.

Common signs include:

• Reduced sex drive

• Erectile difficulties

• Fatigue

• Loss of muscle mass

• Increased body fat

• Mood changes

• Low motivation

• Difficulty concentrating

• Brain fog

• Reduced body hair

However, symptoms alone cannot diagnose low testosterone. Many of these symptoms can also occur with stress, depression, poor sleep, thyroid disorders, and other medical conditions.

A diagnosis requires both symptoms and confirmed low testosterone levels on blood testing.

Diagnosing low testosterone is relatively straightforward but requires appropriate testing.

A testosterone blood test is usually taken in the morning, ideally between 7am and 10am, when testosterone levels are naturally at their highest. Testing is often repeated several weeks later if an initial low result is found because testosterone levels naturally fluctuate from day to day.

Additional blood tests may include:

• Free testosterone

• LH (luteinising hormone)

• FSH (follicle stimulating hormone)

• Prolactin

These tests help identify whether the problem originates in the testes or in the hormone signalling pathways of the brain.

Healthcare professionals will also consider symptoms, medical history, medications, and other health factors when interpreting results.

In many cases, yes.

The most appropriate treatment depends on the underlying cause. For some men, lifestyle changes alone may significantly improve testosterone levels.

Helpful strategies may include:

• Maintaining a healthy weight

• Regular exercise

• Improving sleep quality

• Managing stress

• Reducing alcohol intake

• Avoiding recreational drugs

• Optimising conditions such as diabetes

Not everyone with low testosterone requires testosterone replacement therapy. In many situations, addressing the underlying cause may improve hormone levels naturally.

For men with persistent symptoms and confirmed testosterone deficiency, further medical assessment can help determine whether additional treatment is appropriate.