Male hypogonadism
Symptoms, causes and laboratory evaluation
Recognizing and confirming low testosterone
Key takeaway for patientsLow testosterone is diagnosed from symptoms and repeated blood tests together, never from one result. Many causes, such as weight, sleep and illness, are reversible.
Hypogonadism is the clinical term for low testosterone with symptoms. The symptoms, reduced libido, fewer morning erections, fatigue, low mood and loss of muscle, are common and overlap with many other conditions, so they cannot establish the diagnosis alone.
Diagnosis rests on symptoms together with consistently low morning testosterone on at least two occasions. LH and FSH then show whether the cause lies in the testes (primary) or in the pituitary or hypothalamus (secondary).
Key steps in the evaluation
- Symptoms
- Sexual symptoms are the most specific.
- Morning total testosterone
- Measured fasting, on two separate days.
- SHBG and free testosterone
- Where the total is borderline.
- LH and FSH
- To locate the cause.
Causes and contributing factors
Reversible causes are looked for first:
- Obesity and type 2 diabetes
- The commonest associations in adult men.
- Sleep apnoea and poor sleep
- Reduce the night-time production of testosterone.
- Medicines and alcohol
- Opioids and glucocorticoids among them.
- Pituitary or testicular conditions
- Less common, and important to identify.
Clinical management and physician guidance
The evaluation follows a set order, and what follows from it is a clinical decision.
- Laboratory evaluation
- The tests above, with prolactin and others where indicated.
- Physician-guided care
- Reversible causes are addressed first; any treatment is decided by your physician and carries its own monitoring.
- Monitoring and follow-up
- Symptoms and markers are reviewed over time, and the plan is adjusted to them.
Research focus in male hypogonadism
| Core focus area | Biological target | Clinical relevance |
|---|---|---|
| Diagnosis | Morning total and free testosterone | Thresholds and repeat testing |
| Classification | LH and FSH | Primary and secondary hypogonadism |
| Metabolic links | Obesity and insulin resistance | Functional lowering of testosterone |
| Sleep | Sleep apnoea | Night-time production of testosterone |
Frequently asked questions
- Can symptoms alone show that testosterone is low?
- No. Fatigue, low mood and low libido have many causes; a diagnosis needs blood tests as well.
- Why is the test repeated?
- Levels vary from day to day and with illness, so one low result is not enough.
- Can low testosterone be reversed?
- Where it is caused by weight, poor sleep, illness or a medicine, levels can recover when the cause is addressed.
Academic references and literature
- Wu FC et al. (2010). Identification of late-onset hypogonadism in middle-aged and elderly men. N Engl J Med, 363(2), 123-35. PMID 20554979.
- Basaria S (2014). Male hypogonadism. Lancet, 383(9924), 1250-63. PMID 24119423.
- Brambilla DJ et al. (2009). The effect of diurnal variation on clinical measurement of serum testosterone and other sex hormone levels in men. J Clin Endocrinol Metab, 94(3), 907-13. PMID 19088162.
This guide belongs to the Sexual Health program