Male hormone problems, specifically low testosterone and hypogonadism, occur when there is a disruption in the Hypothalamic Pituitary Gonadal (HPG) axis. This complex system involves the brain signalling the testes to produce testosterone and sperm. When any part of this communication chain is broken, hormone levels fall. In 2026, clinicians categorise these causes into primary, secondary, and lifestyle related factors to determine the best course of treatment.
What We Will Cover in This Article
- Primary causes: Issues directly affecting the testes
- Secondary causes: Breakdowns in brain to testes signalling
- The significant impact of metabolic health and obesity
- Medication induced hormone suppression
- Chronic illnesses and systemic health factors
- 2026 clinical perspectives on environmental and lifestyle causes
Primary Causes: Issues Within the Testes
Primary hypogonadism occurs when the testes themselves are damaged or dysfunctional. In this case, the brain sends the signal to produce testosterone, but the testes cannot respond.
- Genetic Conditions: Klinefelter Syndrome, where a male has an extra X chromosome (XXY), is a common genetic cause of testicular failure.
- Physical Trauma or Injury: Significant injury to the testes or a history of undescended testes can permanently affect hormone production.
- Medical Treatments: Chemotherapy or radiation therapy for cancer can damage the cells responsible for producing testosterone.
- Infections: Mumps orchitis, an infection of the testes occurring during or after puberty, can lead to permanent damage.
Secondary Causes: Issues Within the Brain
Secondary hypogonadism happens when the hypothalamus or the pituitary gland in the brain fails to send the necessary hormonal signals, such as LH and FSH, to the testes.
- Pituitary Disorders: Tumours, usually non cancerous, on the pituitary gland can interfere with hormone production.
- Inflammatory Diseases: Conditions like sarcoidosis or tuberculosis can affect the hypothalamus and pituitary.
- Kallmann Syndrome: A genetic condition that affects the development of the hypothalamus, often characterised by a delayed start to puberty and a reduced sense of smell.
- Severe Physical Stress: Chronic overtraining, extreme weight loss, or severe systemic illness can cause the brain to temporarily shut down hormone production to conserve energy.
Metabolic Health and Lifestyle Factors
In the modern clinical landscape of 2026, metabolic health is recognised as a leading driver of low testosterone.
- Obesity: Excess body fat is not just stored energy; it is metabolically active. Fat tissue contains an enzyme called aromatase, which converts testosterone into oestrogen. Furthermore, obesity can cause systemic inflammation that suppresses brain signalling.
- Type 2 Diabetes: Men with insulin resistance are at a much higher risk of low testosterone, as high insulin levels interfere with the HPG axis.
- Sleep Apnoea: Chronic sleep disruption and low oxygen levels during the night significantly lower morning testosterone production, which primarily occurs during deep sleep.
Medication and Substance Induced Suppression
Certain substances and medications can suppress the body natural hormone production, sometimes permanently.
- Opioid Painkillers: Long term use of opioids is a well documented cause of secondary hypogonadism.
- Anabolic Steroids: Taking exogenous testosterone or steroids causes the brain to stop producing its own hormones. This can lead to significant testicular shrinkage and long term deficiency even after stopping the drugs.
- Glucocorticoids: Long term use of steroid medications like prednisone for inflammatory conditions can suppress testosterone.
- Alcohol Abuse: Chronic excessive alcohol consumption is toxic to the testes and interferes with hormone metabolism in the liver.
To Summarise
The causes of low testosterone are diverse, ranging from irreversible genetic conditions to modifiable lifestyle choices. Determining whether the root cause is in the testes (primary) or the brain (secondary) is the first step in clinical management. In 2026, we increasingly find that addressing metabolic health, sleep, and medication use is just as important as hormone replacement therapy itself. Understanding why your levels are low ensures that the treatment addresses the cause, not just the symptom.
If you experience sudden loss of libido, significant muscle wasting, or persistent low mood, seek a clinical review with your GP to begin the diagnostic process.
Can stress alone cause low testosterone?
Yes. High levels of cortisol, the stress hormone, can actively inhibit the production of testosterone by suppressing the signals from the brain.
Is low testosterone always permanent?
Not necessarily. If the cause is lifestyle related, such as obesity or sleep apnoea, or caused by certain medications, levels may recover once those factors are addressed.
How does ageing affect these causes?
Ageing typically results in a slow decline in both testicular function and brain signalling. This is often called late onset hypogonadism.
Can head injuries cause hormone problems?
Yes. A traumatic brain injury (TBI) can damage the pituitary gland or hypothalamus, leading to secondary hypogonadism years after the injury occurred.
Does carrying weight around the stomach lower testosterone?
Specifically, yes. Visceral fat, or abdominal fat, is highly associated with lower testosterone because it promotes inflammation and the conversion of testosterone to oestrogen.
Can I have low testosterone if my lifestyle is healthy?
Yes. If the cause is primary, such as testicular damage or genetic factors, a healthy lifestyle may not be enough to maintain normal hormone levels.
Authority Snapshot
This article was written by the MyPatientAdvice clinical team and reviewed by Dr. Stefan Petrov, a UK trained physician with an MBBS and extensive experience in general medicine, surgery, and emergency care. Dr. Petrov has postgraduate certifications including Basic Life Support (BLS), Advanced Cardiac Life Support (ACLS), and the UK Medical Licensing Assessment (PLAB 1 & 2). He is a specialist in medical education and creating patient focused health content. This information follows 2024 and 2026 clinical protocols for identifying causes of male hormonal health issues.
