Low Testosterone Symptoms in Men Over 40

The most common signs of low testosterone in men over 40 are low sex drive, tiredness that rest does not fix, loss of muscle strength, more body fat around the middle, and low mood or poor concentration. These symptoms overlap with normal ageing and many other conditions, so a blood test is the only way to know whether testosterone is actually low.

Testosterone falls gradually with age, by roughly 1% a year from the late 30s onwards (Cleveland Clinic, 2026). For most men that slow decline causes no problems. A smaller group has genuinely low levels worth investigating. This guide covers the symptoms to notice, what causes them, how the condition is diagnosed in Australia, and when to see a doctor.

What is low testosterone?

Low testosterone, also called androgen deficiency or hypogonadism, means the body is not making enough testosterone for good health. In Australia it affects somewhere between 1 in 20 and 1 in 200 men, depending on the cause (Healthy Male).

There is an important difference between age-related decline and a medical deficiency. Levels drifting down slowly over decades is normal. A deficiency is a low reading on a blood test paired with symptoms, often driven by a treatable cause rather than age alone.

Common symptoms of low testosterone

Symptoms tend to be non-specific, which is why testing matters. The signs below are grouped to make them easier to recognise.

Physical signs

• Ongoing fatigue that sleep does not resolve
• Loss of muscle strength and mass despite regular training
• More body fat, particularly around the abdomen
• Reduced body or facial hair
• Hot flushes and sweating
• Lower bone density over the long term, which raises fracture risk

Sexual signs

• Reduced sex drive
• Fewer morning or spontaneous erections
• Erectile difficulties, often alongside other causes
• Low sperm count and reduced fertility

Mood and thinking

• Low mood or irritability
• Poor concentration and memory, sometimes described as brain fog
• Disturbed sleep

No single symptom confirms low testosterone. Several together, especially reduced libido, loss of morning erections and shrinking testicles, make it more likely and are worth raising with a doctor (Cleveland Clinic, 2026).

What causes low testosterone in men over 40?

Testosterone can fall for reasons that have nothing to do with age, and several are reversible. Common contributors include:

• Carrying excess weight, particularly around the abdomen
• Type 2 diabetes
• Obstructive sleep apnoea
• Heavy alcohol use
• Chronic stress and poor sleep
• Some medications, including opioids and corticosteroids

Medical causes fall into two groups. Primary hypogonadism comes from a problem in the testes, such as injury, mumps, or a genetic condition like Klinefelter syndrome, which affects roughly 1 in 450 to 700 Australian men (Hormones Australia). Secondary hypogonadism comes from the pituitary gland or hypothalamus, the parts of the brain that signal the testes to produce testosterone.

Because weight, sleep and medications all play a part, addressing those often improves levels without any other treatment.

How is low testosterone diagnosed in Australia?

Testosterone cannot be diagnosed on symptoms alone. Diagnosis rests on a blood test, and timing matters because levels are highest in the morning and vary through the day. The usual process:

• A blood sample taken between 8am and 10am, ideally fasting
• A second morning sample on a different day to confirm the result, since one low reading is not enough (Australian Prescriber, 2014)
• Additional tests such as luteinising hormone (LH), follicle-stimulating hormone (FSH) and sex hormone binding globulin (SHBG) to work out the cause
• Further checks where needed, including prolactin, iron studies and a bone density scan

For healthy young men the Australian reference range runs from about 9.7 to 34.3 nmol/L (Australian Prescriber, 2014). Under the Pharmaceutical Benefits Scheme, subsidised testosterone for a man over 40 without established pituitary or testicular disease requires a level below 8 nmol/L, or below 15 nmol/L with a raised LH, confirmed on at least two occasions (Australian Prescriber, 2014).

A quiz or symptom checklist can flag whether testing is worth doing, but it cannot diagnose the condition. That is a job for a doctor and a blood test. You can start with our hormone assessment if you want a structured way to review your symptoms first.

When should you see a doctor?

Book a review if several of these have persisted for weeks and are affecting daily life:

• A sex drive that has dropped noticeably
• Fatigue heavy enough to affect work or relationships
• Ongoing low mood
• Loss of muscle or unexplained weight gain

Keep your regular GP in the loop whatever you decide. Low testosterone often sits alongside conditions like diabetes or sleep apnoea, and joined-up care works best. If low mood is the main issue, speak to your GP or a psychologist, since mood has many causes beyond hormones.

How is low testosterone managed?

Management depends on the cause, and a registered doctor decides what is appropriate after assessment. Not everyone with symptoms needs or is suitable for hormone treatment.

The first step is usually to address reversible factors. Losing excess weight, treating sleep apnoea, cutting back on alcohol, improving sleep and building regular resistance exercise can all lift testosterone and improve how you feel. Our guides on lifestyle changes that support testosterone and sleep and hormones cover this in detail.

Where a genuine deficiency is confirmed, testosterone replacement therapy is one option a doctor may consider. It is prescribed only when clinically appropriate, is not suitable for everyone, and needs ongoing monitoring with blood tests. The evidence for treating men who have low-normal levels and vague symptoms, rather than a clear deficiency, is limited (Australian Prescriber, 2014), which is why careful assessment comes first. Menova's doctors work through this with you rather than assuming treatment is the answer.

If weight is part of the picture, our weight management and hormone restoration programmes may be relevant, again subject to a consultation.

Frequently asked questions

How common is low testosterone in men over 40?

Androgen deficiency affects somewhere between 1 in 20 and 1 in 200 Australian men depending on the cause. It becomes more likely with age, and with conditions such as obesity, type 2 diabetes and sleep apnoea, which are all more common after 40.

Can low testosterone be improved without medication?

Often, yes. Losing excess weight, treating sleep apnoea, cutting back on alcohol, improving sleep and doing regular resistance exercise can all help raise testosterone. Whether that is enough depends on your levels and the underlying cause, which a doctor can assess.

What blood test is used to diagnose low testosterone?

A morning blood test measuring total testosterone, ideally between 8am and 10am while fasting. Because levels fluctuate, a second morning sample on a different day is needed to confirm a low result. Extra hormones such as LH, FSH and SHBG help identify the cause.

Is low testosterone the same as erectile dysfunction?

No. They are separate but related. Low testosterone can reduce sex drive and contribute to erectile difficulties, but erections also depend on blood flow, nerves and psychological factors. Many men with erectile issues have normal testosterone. Our guide on erectile dysfunction explains the difference.

Does testosterone naturally decline with age?

Yes. Testosterone falls by roughly 1% a year from the late 30s. For most men this gradual decline causes no significant problems and does not require treatment. A blood test can show whether a low reading reflects normal ageing or a deficiency worth acting on.

Are at-home testosterone tests reliable?

At-home kits can be a starting point, but results vary between laboratories and a single reading is not enough to diagnose the condition. A proper diagnosis uses two morning samples and additional hormone tests interpreted by a doctor, so treat a home result as a prompt to get checked.

What happens at a testosterone consultation?

A doctor reviews your symptoms and health history, arranges the appropriate blood tests, and interprets the results in context. If a deficiency is confirmed, they discuss whether treatment is suitable for you and how it would be monitored. Not everyone is eligible, and the consultation is the first step.

References

• Cleveland Clinic. Low testosterone (male hypogonadism). 2026. https://my.clevelandclinic.org/health/diseases/15603-low-testosterone-male-hypogonadism
• Perry-Keene D. Low testosterone in men. Australian Prescriber. 2014. https://australianprescriber.tg.org.au/articles/low-testosterone-in-men.html
• Healthy Male. Low testosterone. https://healthymale.org.au/mens-health/low-testosterone
• Hormones Australia (Endocrine Society of Australia). Hypogonadism. https://www.hormones-australia.org.au/endocrine-diseases/hypogonadism/
• Healthdirect. Testosterone. 2024. https://www.healthdirect.gov.au/testosterone