Hypogonadism
1 medicine
Hypogonadism is a condition where the testes or ovaries produce too little sex hormone, most often causing low testosterone in men, treated with hormone replacement.
Key facts
- Hypogonadism means the testes or ovaries fail to produce enough sex hormone. In men, the most affected group, this shows up as chronically low testosterone.
- Low testosterone affects energy, libido, mood, bone density and muscle mass, and can develop at any age, though it becomes more common later in life.
- A blood test measuring morning testosterone, LH and FSH tells doctors whether the problem starts in the testes (primary) or higher up, in the pituitary or hypothalamus (secondary).
- Treatment is testosterone replacement, which brings hormone levels back into the normal range and relieves symptoms gradually over months.
What hypogonadism is
Hypogonadism occurs when the testes or ovaries fail to produce adequate sex hormones. In men, this means chronically low testosterone, which affects energy, libido, mood, bone density and muscle mass. It can develop at any age, though it becomes more prevalent with age and is increasingly recognised alongside metabolic conditions such as type 2 diabetes or obesity.
Why testosterone levels fall
Primary hypogonadism originates in the testes themselves: damage from trauma, infection (including mumps orchitis), or genetic conditions such as Klinefelter syndrome. Secondary hypogonadism arises higher up, when the pituitary gland or hypothalamus fails to send the right signals, often due to a tumour, iron overload, or prolonged use of certain medicines. A simple blood test measuring morning testosterone, LH and FSH distinguishes the two types and guides treatment.
Restoring hormone levels
Hormone therapy is the mainstay of treatment. Testosterone replacement brings levels back into the normal range, relieving fatigue, improving sexual function, and supporting bone and muscle health over time. Response is gradual: most men notice meaningful improvement within a few months of consistent therapy. Regular monitoring of blood count, prostate health and hormone levels is standard practice during long-term treatment.
When to see a doctor
See a doctor if you notice persistent fatigue, low libido, low mood or unexplained loss of muscle mass, especially alongside other symptoms of low testosterone. Diagnosis needs a blood test, so do not start hormone treatment without one.
This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.