Testosterone

How it works

It replaces endogenous androgen, binding androgen receptors to restore secondary sexual characteristics, libido, muscle and bone mass, and to suppress the symptoms of deficiency.

Prescribing in practice

• It is contraindicated in known or suspected prostate or breast cancer and must only be started after biochemically confirmed deficiency on morning samples.
• Therapy can raise haematocrit (causing polycythaemia and thrombotic risk) and may worsen lower urinary tract symptoms or unmask prostate disease.
• Topical gels can transfer to partners and children on skin contact, so application sites should be covered and washed.

Monitoring

Monitor testosterone levels, haematocrit, prostate-specific antigen and prostate symptoms before and periodically during treatment.

Counselling the patient

• With gels, cover the application area and avoid skin-to-skin contact with women and children until absorbed.
• Attend blood tests as scheduled to check red cell count and prostate marker.

Evidence & guidelines

Endocrine and urology guidelines recommend testosterone replacement only for symptomatic, biochemically confirmed hypogonadism, with structured safety monitoring.