Secondary Hypogonadism

Key facts

• Secondary hypogonadism is a hormonal disorder in which the pituitary gland or hypothalamus fails to send adequate signals to the testes or ovaries, so sex hormone levels fall even though the gonads themselves are healthy.
• In men it typically causes reduced libido, fatigue, loss of muscle mass, mood changes, and infertility; in women it can cause irregular or absent periods and difficulty conceiving.
• Common causes include pituitary tumours (particularly prolactinoma), head injury, obesity, chronic opioid use, and significant psychological stress.
• Treatment targets the root cause where possible; testosterone replacement or oestrogen-based regimens can relieve symptoms, but specialist endocrine review is essential before starting any hormone therapy.

Why the signalling breaks down

The hypothalamus releases gonadotropin-releasing hormone, which prompts the pituitary to produce LH and FSH. These two hormones then tell the testes or ovaries to produce sex hormones and, in men, sperm. Secondary hypogonadism disrupts this chain at the hypothalamic or pituitary level rather than at the gonads themselves. Common causes include pituitary tumours, in particular prolactinoma, head injuries, obesity, chronic opioid use, and significant psychological stress. Undiagnosed sleep apnoea is also increasingly recognised as a contributor, since it suppresses the overnight hormone pulses the system depends on.

Recognising the condition

In men, low testosterone typically causes reduced libido, fatigue, loss of muscle mass, mood changes, and infertility. In women, disrupted gonadotropins can cause irregular or absent periods and difficulty conceiving. Blood tests measuring LH, FSH, and sex hormone levels, alongside pituitary imaging where appropriate, confirm the diagnosis and distinguish it from primary gonadal failure, where the fault lies in the testes or ovaries directly.

Treatment approach

Treatment depends on the root cause. Where a correctable cause exists, such as a prolactinoma or severe obesity, addressing that often restores normal hormone output. When direct hormone replacement is appropriate, testosterone therapy in men or oestrogen-based regimens in women, part of the wider hormones range, can relieve symptoms. Men wanting to preserve or restore fertility are typically treated with gonadotropin injections rather than direct testosterone, since testosterone replacement suppresses the body's own LH and FSH. Specialist endocrine review is essential before starting any hormone therapy.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.