TRT UK: A Complete Guide to Testosterone Replacement Therapy in the UK

Testosterone Replacement Therapy (TRT) is a medical treatment used to address clinically low testosterone levels in men. In the UK, access to TRT, eligibility criteria, costs, and treatment pathways differ significantly between the NHS and private clinics.
This guide explains how TRT works in the UK, who may be eligible, how diagnosis is made, potential benefits and risks, and the differences between NHS and private treatment — using current UK clinical practices.

Clinical studies indicate that biochemical testosterone deficiency affects approximately 2–6% of middle-aged and older men, with prevalence increasing with age. This estimate is supported by large European population data from the European Male Ageing Study (EMAS), which is frequently referenced in UK clinical guidance.

Reference: European Male Ageing Study (PubMed) – https://pubmed.ncbi.nlm.nih.gov/22419720/

TRT (Testosterone Replacement Therapy) is a medically prescribed treatment used to restore testosterone levels in men with confirmed testosterone deficiency (hypogonadism).

Testosterone plays a key role in:

• Energy levels and fatigue
• Libido and sexual function
• Mood and cognitive function
• Muscle mass and bone density
• Overall metabolic health

TRT aims to restore testosterone to a healthy physiological range — not to enhance performance or exceed normal levels.

Yes, TRT is legal in the UK when prescribed by a qualified medical professional following appropriate diagnostic testing.

Testosterone is classified as a prescription-only medication. It cannot be legally obtained without:

• Blood test confirmation of low testosterone
• Clinical assessment of symptoms
• Ongoing medical supervision

Using testosterone without a prescription, or obtaining it from unregulated sources, is illegal and potentially dangerous.

Eligibility is based on both symptoms and blood test results.

Common symptoms of low testosterone include:

• Persistent fatigue
• Low libido or erectile dysfunction
• Depression or low mood
• Reduced muscle mass and strength
• Increased body fat
• Brain fog or poor concentration

Diagnostic criteria typically involve:

• Morning blood tests (usually between 7–11am)
• Repeated low total testosterone readings
• Consideration of free testosterone, SHBG, and related markers
• Exclusion of reversible or underlying causes

A diagnosis should never be made on symptoms alone.

Diagnosis usually involves:

1. Initial blood testing (e.g., total testosterone, free testosterone or calculated free testosterone, SHBG, LH, FSH, oestradiol, prolactin).
2. Clinical consultation to review symptoms, medical history, lifestyle factors, and fertility considerations.
3. Repeat testing to confirm consistently low levels.

Both NHS endocrinologists and private clinicians follow broadly similar diagnostic principles, though thresholds and interpretation may vary.

In the UK, both the NHS and private clinicians diagnose low testosterone using morning blood tests and clinical symptoms, but they apply different treatment thresholds.

On the NHS, TRT is usually offered only when testosterone levels are clearly low, typically below 8 nmol/L on repeat testing. Men with results between 8–12 nmol/L are often assessed conservatively and may not qualify for treatment unless there is a clear underlying medical cause.

In private care, clinicians still follow recognised clinical guidance but often take a more individualised approach. Testosterone levels in the 8–12 nmol/L range may be interpreted alongside symptoms, SHBG, and calculated free testosterone, meaning some symptomatic men who do not meet NHS treatment thresholds may still be considered for TRT with appropriate monitoring.

In all cases, TRT should not be prescribed based on symptoms alone and requires ongoing medical supervision.

Reference: Norfolk & Norwich University Hospitals NHS – Adult Testosterone Replacement and Monitoring Guideline (2024): https://www.nnuh.nhs.uk/publication/download/adult-testosterone-replacement-and-monitoring-jcg0043-v4/

TRT on the NHS:

• Typically reserved for clear, severe hypogonadism
• Long waiting times are common
• Limited treatment options in some regions
• Strict diagnostic thresholds

NHS TRT Access Criteria

Within the NHS, testosterone replacement therapy is generally reserved for men with confirmed biochemical hypogonadism. Men with borderline testosterone levels but significant symptoms may not meet NHS treatment thresholds depending on overall clinical assessment.

Reference: NHS patient guidance on male hypogonadism and testosterone testing – https://www.nhs.uk/conditions/male-menopause/

Private TRT in the UK:

• Faster access
• More comprehensive hormone testing
• Individualised dosing and monitoring
• Wider choice of treatment methods

Many men pursue private TRT after being declined NHS treatment despite persistent symptoms.

The table below compares key differences between NHS and private Testosterone Replacement Therapy (TRT) in the UK.

Injections

• Testosterone enanthate or cypionate
• Often administered weekly or twice weekly
• Commonly prescribed privately due to flexible dosing

Gels

• Daily topical application
• Absorption can vary between individuals

Long-acting injections

• Less frequent dosing
• Often used in NHS settings
• Less flexibility in dose adjustment

The best option depends on clinical needs, lifestyle, response to treatment, and monitoring requirements.

When clinically appropriate and properly monitored, TRT may help improve:

• Energy and motivation
• Libido and sexual function
• Mood stability
• Muscle strength and body composition
• Bone density
• Overall quality of life

Benefits typically develop gradually over weeks to months.

Like any medical treatment, TRT carries potential risks, including:

• Raised haematocrit
• Oestradiol imbalance
• Acne or oily skin
• Suppression of natural testosterone production
• Fertility suppression (in some cases)

Ongoing monitoring is essential and usually includes:

• Regular blood tests (commonly testosterone, oestradiol, haematocrit, lipids)
• Symptom review
• Dose adjustments where needed
• Long-term cardiovascular and prostate health considerations

TRT is not a one-time treatment, but a long-term medical therapy.

Long-term TRT safety depends on appropriate dosing and regular monitoring. UK clinical recommendations emphasise monitoring haematocrit, testosterone levels, and oestradiol, as TRT-associated erythrocytosis has been reported in a proportion of treated patients without adequate follow-up.

Reference: NHS patient TRT leaflet – https://www.ncic.nhs.uk/patients-visitors/patient-information-leaflets/Testosterone-replacement-therapy

Reference: British Society for Sexual Medicine (BSSM) Guidelines – https://bssm.org.uk/wp-content/uploads/2023/02/guidelines-on-adult-testosterone-deficiency-with-statements-for-uk-practice.pdf

Costs vary depending on whether treatment is NHS or private.

Private TRT typically includes:

• Initial consultation and blood tests
• Ongoing prescriptions
• Regular monitoring

Monthly costs often range from £100–£200, depending on treatment type and testing frequency.

TRT may be long-term or lifelong for men with irreversible testosterone deficiency. In some cases, treatment may be paused or reassessed if underlying causes are addressed. A clinician should regularly review whether TRT remains appropriate.

• TRT is legal and regulated in the UK when prescribed appropriately.
• Diagnosis requires blood tests and symptoms — not symptoms alone.
• NHS access is limited and often involves strict thresholds and waiting times.
• Private TRT usually provides faster access and more individualised monitoring.
• Long-term monitoring is essential for safety and effectiveness.