What Are the Side Effects of Hormone Therapy for Prostate Cancer?

Originally published: 2020 | Updated: March 2026

Reading Time: 6 minutes
Medically reviewed on: March 20th 2026. Mr Raj Nigam Consultant Urologist. MBBS, FRCS, FRCS (Urol), FEBU, MD  GMC: 3265226
Authors: Ms Clare Delmar. The Focal Therapy Clinic

What Is Hormone Therapy for Prostate Cancer?

Hormone therapy — also called androgen deprivation therapy (ADT) — is a well-established treatment for advanced and metastatic prostate cancer. It works by reducing testosterone levels to slow cancer cell growth. For men with cancer that has spread to the bones or lymph nodes, hormone therapy is an essential part of disease management recommended under NICE Guideline NG131.

However, the trade-offs between cancer control and quality of life are significant. Hormone therapy affects physical health through muscle wasting, bone density loss and sexual dysfunction — and increasingly, research shows it impacts mental health too, contributing to depression, brain fog and mood changes.

“The effects of testosterone on the brain are under-recognised and underplayed. Men on hormone therapy often complain of a loss of cognition, brain fog, mood changes and depression.”

When Is Hormone Therapy Necessary?

Hormone therapy is essential for men with advanced prostate cancer — particularly those with metastatic disease that has spread to the bones or lymph nodes. It is also used as a pre-radiotherapy preparation, where a three-month course of androgen deprivation therapy can improve treatment outcomes.

However, Mr Raj Nigam, Consultant Urological Surgeon and Andrologist at The Focal Therapy Clinic (FRCS(Urol), GMC: 3265226), raises concern that some men with early-stage, localised prostate cancer are being started on hormone therapy when alternative treatments may be more appropriate.

“We see men with early-stage prostate cancer who have been placed on hormones without a full discussion of their options. There are some men who absolutely need hormone therapy — those with metastatic disease or those preparing for radiotherapy. But for many men with localised disease, there are alternatives that should be discussed first.”

For men with localised, early-stage prostate cancer, focal therapy options such as HIFU (NICE IPG424) and NanoKnife IRE (NICE IPG768) offer targeted treatment that preserves quality of life. In The Focal Therapy Clinic’s audit of 265 patients, 90%+ maintained sexual function and 97% maintained urinary continence after focal therapy.

Who Should Be on Hormone Therapy?

Not every man diagnosed with prostate cancer needs hormone therapy. At The Focal Therapy Clinic, Mr Raj Nigam identifies three distinct groups:

• Men with metastatic disease — cancer that has spread to bones or lymph nodes requires hormone therapy to control disease progression
• Men preparing for radiotherapy — a three-month course of androgen deprivation therapy before radiotherapy has been shown to improve treatment outcomes
• Men with early-stage, localised cancer — these men may have alternative options including focal therapy, active surveillance, or other targeted treatments

If you have been placed on hormone therapy for early-stage prostate cancer and are experiencing side effects, it is worth discussing your full range of options — including a second opinion — with a specialist who can review your individual case.

What Are the Physical Side Effects of Hormone Therapy?

Hormone therapy works by reducing testosterone levels, which slows prostate cancer growth but also affects many other body systems. Mr Raj Nigam, who also specialises in Andrology (the study of male hormonal health), sees the impact of low testosterone regularly in his clinics — both in men on hormone therapy and those with naturally low testosterone levels.

The physical side effects of prostate cancer hormone therapy include:

• Sexual dysfunction — loss of libido, erectile difficulties, and ejaculatory problems are common and can significantly affect confidence and relationships
• Muscle wasting — reduced testosterone leads to loss of muscle mass and strength, making everyday activities more tiring
• Bone density loss — long-term hormone therapy increases the risk of osteoporosis, particularly after 12 months or more of treatment
• Fatigue and weakness — persistent tiredness, reduced motivation for exercise, and a general feeling of physical depletion
• Weight gain — changes in body composition with increased fat and reduced lean muscle
• Hot flushes — sudden episodes of heat and sweating, similar to menopausal symptoms

“These are real physical issues that men experience whilst on hormonal therapy. The sexual side effects — loss of libido, erectile difficulties — can lead to a complete loss of confidence. And the effects on muscle mass and bone density, particularly with longer-term treatment, can lead to early fatigue and a constant feeling of weakness.”

How Does Hormone Therapy Affect Mental Health?

The mental health impact of prostate cancer hormone therapy is under-recognised and underplayed, according to Mr Raj Nigam. Low testosterone levels — whether caused by hormone therapy or occurring naturally — are associated with cognitive changes, mood disturbance and clinical depression. For men who are still working, these effects can be particularly disruptive.

Mental health side effects of hormone therapy include:

• Cognitive changes — difficulty concentrating, slower speed of thought, and memory problems (commonly described as “brain fog”)
• Mood changes — increased irritability, emotional instability, and reduced motivation
• Depression — clinically significant depression is a recognised side effect of androgen deprivation therapy
• Loss of confidence — the combined physical and psychological effects can lead to social withdrawal and reduced quality of life

“The effects of testosterone on the brain are under-recognised and underplayed. Men in my Andrology clinics often complain of a loss of cognition, a loss in the speed of thought — brain fog symptoms. We know that mood changes and depression are associated with low testosterone levels, and hormone therapy induces exactly that.”

If you are experiencing mental health effects from hormone therapy, discuss this with your urologist or GP. The British Association of Urological Surgeons (BAUS) and NICE Guideline NG131 recommend that men on hormone therapy should be monitored for psychological side effects.

What Are the Alternatives to Hormone Therapy for Early-Stage Prostate Cancer?

For men with localised, early-stage prostate cancer, hormone therapy is not the only option. Focal therapy treatments target the cancer directly while preserving surrounding healthy tissue, avoiding the systemic side effects of hormone therapy.

Source: FTC one-year outcome audit (n=265) and published literature

At The Focal Therapy Clinic, our consultants have collectively performed over 2,000 focal therapy procedures across seven UK locations. If you have been placed on hormone therapy for early-stage prostate cancer and would like to explore alternatives, book a consultation or call +44 (0) 207 036 8870.

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