Male Hypogonadism, Erectile Dysfunction and Testosterone Therapy

Diagnosis before treatment and a clear view of fertility safety
Clinical review: September 2026
 
Testosterone is important, but it is not a personality trait in a vial. It influences sexual function, bone, muscle, red-cell production and wellbeing; it is also only one part of a larger endocrine and vascular conversation.

Diagnosing low testosterone properly
Male hypogonadism means the testes do not produce enough testosterone or sperm because of a testicular problem, or because the brain-pituitary signal that directs them is reduced. Symptoms matter, but so do repeated early-morning testosterone results and related tests such as LH, FSH, prolactin and SHBG. One low result after illness, poor sleep or a difficult week is not a diagnosis.

Erections are a blood-flow story as well as a hormone story
Erectile dysfunction can reflect diabetes, blood pressure, cholesterol, smoking, low testosterone, medicines, pelvic surgery, neurological conditions, anxiety or relationship factors.

Testosterone therapy may help sexual desire and sometimes erectile function in men with confirmed hypogonadism; it is not a universal treatment for erectile dysfunction. PDE5 inhibitors are commonly effective for suitable men, but require attention to cardiovascular safety and must not be used with nitrates.

What testosterone therapy can and cannot do
For confirmed hypogonadism, testosterone replacement can improve symptoms and body composition over time. The form - gel, injection or another preparation - is chosen around preference, levels, safety and practicalities. Monitoring is not bureaucracy with extra forms: it checks symptom response, testosterone level, blood count and prostate-related issues where appropriate.

The fertility sentence in bold
Exogenous testosterone reduces the brain signals needed for sperm production and can markedly suppress fertility. It is therefore usually inappropriate for someone trying to conceive. Fertility-preserving options depend on the diagnosis and should be discussed with an experienced clinician rather than improvised online.

Important safety note
Seek urgent help for chest pain, breathlessness, a prolonged painful erection, sudden severe headache or visual symptoms. Testosterone treatment should not be started without confirmed diagnosis and a monitoring plan.

Further reading

• Endocrine Society testosterone therapy guideline

• NHS erectile dysfunction

• NHS infertility diagnosis

• WHO laboratory manual for semen 2021