Male hypogonadism: low testosterone symptoms, causes, tests and treatment

The testes make testosterone, the main male sex hormone, and sperm. Hypogonadism is when they produce few or no hormones. The NHS describes two broad timings: present from birth, which can cause delayed puberty and small testes, or developing later in life, particularly in men who are obese or have type 2 diabetes.

The problem can sit in the testes themselves (primary hypogonadism) or higher up, in the pituitary gland or brain, which signal the testes to work (secondary hypogonadism). The NHS Highland guideline points out that lower testosterone levels are more common in secondary causes, whereas milder deficiency may suggest illness elsewhere in the body or late-onset hypogonadism linked to increasing age and obesity. Opioid medicines can also be involved in some men.

A low testosterone reading on its own is not the diagnosis. The guideline stresses that a clinical syndrome needs both symptoms and blood evidence, because testosterone varies and other conditions can lower it temporarily.

The NHS describes symptoms in men in their late 40s to early 50s that can come from several causes. The ones the NHS Highland guideline considers most closely tied to low testosterone are erectile dysfunction, loss of spontaneous or early-morning erections and reduced libido. Low bone mineral density and a mild anaemia can also be features.

Other symptoms listed by the NHS include mood swings and irritability, loss of muscle mass and reduced ability to exercise, fat redistribution such as a larger belly or enlarged breast tissue (gynaecomastia), low energy, difficulty sleeping or increased tiredness, and poor concentration and short-term memory. Because these overlap with depression, stress and poor sleep, they cannot be used alone to diagnose a hormone problem.

• Reduced sex drive, erection problems or fewer morning erections.

• Tiredness, low mood, irritability and poor concentration.

• Loss of muscle mass and strength, and increased belly fat.

• Enlarged breast tissue.

• In young people: delayed puberty or small testes.

The NHS calls male menopause an unhelpful term. It suggests a sudden drop in testosterone in middle age similar to the female menopause, which does not happen. Testosterone declines slowly, by about 1% a year from around 30 to 40.

That does not mean a real deficiency never occurs. A deficiency that develops later in life can occasionally be responsible, but the NHS says in many cases symptoms have nothing to do with hormones. It also lists lifestyle contributors including lack of sleep, a poor diet, lack of exercise, too much alcohol, smoking and low self-esteem, and personal factors such as work, relationship or money worries.

A GP therefore starts with questions about work and personal life and about mental health. The NHS says talking therapies such as CBT, exercise and relaxation may help when stress or anxiety are involved, and a blood test for testosterone can be arranged alongside that conversation.

Causes include inherited or developmental conditions, pituitary problems, testicular injury or disease, and general illness or obesity. Klinefelter syndrome, where a boy is born with an extra X chromosome, is a recognised genetic cause: the NHS says the extra chromosome may interfere with testicular development so the testes produce less testosterone than usual. Many men with it do not realise they have it, and in many cases it is only found during fertility tests.

The NHS Highland guideline describes a stepwise approach. If the history suggests it, testosterone is measured, and results guide further hormone tests, including those that show whether the pituitary is signalling the testes. A diagnosis in the NHS usually depends on symptoms and repeated blood tests, interpreted by an endocrinologist where needed.

For mild deficiency with suspected illness elsewhere, the NHS Highland guideline says lifestyle measures and weight loss should be encouraged, and that losing 5 to 10% of body weight may improve testosterone concentrations. In obvious hypogonadism, for example Klinefelter syndrome or hypopituitarism, endocrinologists generally recommend testosterone replacement. In borderline cases, a 3 to 6 month trial may be considered after counselling about benefits and risks.

The NHS says replacement may be given as an injection or a gel. The same guideline notes that long-term risks and cardiovascular safety are unknown, that treatment has not been shown to cause prostate cancer but may promote its growth, that it can worsen or unmask symptoms of benign prostate enlargement, and that some studies have shown an increased risk of blood clots, atrial fibrillation and fractures. It also states there is no guarantee that erectile dysfunction will improve.

It lists situations where treatment is not suitable, including a wish to father children, current prostate or breast cancer, a raised haematocrit, an unevaluated raised PSA or prostate lump, severe heart failure, liver tumour, high calcium and nephrotic syndrome. Anyone planning a family should raise this with the specialist first. Specific products and doses are matters for the prescriber and are not covered here.

The NHS Highland guideline says a full blood count, PSA where applicable, lipids and liver function tests should be checked before starting replacement and repeated at 3, 6 and 12 months, then annually. The haematocrit in particular is monitored to avoid the blood becoming too thick (polycythaemia).

For prostate checks, it says UK Society for Endocrinology guidance does not recommend routine screening with PSA and examination during treatment, but a baseline PSA is usually checked and monitoring is used for men over 45 and in higher-risk individuals, such as those of black ethnicity or with a first-degree relative diagnosed with prostate cancer under 60.

If there has been no clinical improvement despite adequate replacement in men with milder deficiency, the guideline says stopping at 3 to 6 months should be considered. Long-term care of conditions that go with low testosterone, such as bone thinning, diabetes and weight, continues alongside.