TRT UK: What Men Over 40 Need to Know (2026 Guide)

Testosterone replacement therapy (TRT) is one of the most discussed and most misunderstood interventions in men's health. It's simultaneously over-prescribed in certain private clinic contexts and drastically under-prescribed in NHS settings - leaving men with genuinely low testosterone either on inappropriate treatment or unable to access appropriate treatment.

This is the guide I wish had existed when I first started researching this topic. Once you have decided TRT is the right call, my overview of the leading TRT clinics in the UK is the next stop for narrowing down a provider.

If you work in a safety-sensitive role and are considering TRT, there is a specific compliance angle worth understanding — see my piece on drug testing and testosterone therapy for men.

What TRT Actually Is

TRT is the medical replacement of testosterone in men whose bodies are producing insufficient amounts - a condition called hypogonadism. The goal is to restore testosterone to a physiologically normal range, not to elevate it above normal for performance purposes.

The distinction matters. TRT for diagnosed hypogonadism is legitimate medicine. Using exogenous testosterone in men with normal testosterone to achieve supraphysiological levels is anabolic steroid use - a completely different clinical and risk category.

Diagnosing Hypogonadism: What the Thresholds Actually Mean

Hypogonadism in men is formally defined as:

• Primary hypogonadism: Low testosterone with high LH/FSH - the testes aren't responding to the signal
• Secondary hypogonadism: Low testosterone with low or normal LH/FSH - the brain isn't sending the signal

The diagnosis requires two morning (before 10am, fasted) total testosterone measurements below 12 nmol/L (approximately 346 ng/dL), taken at least 4 weeks apart, combined with symptoms.

This is where NHS practice diverges significantly from evidence. The NHS cut-off of 12 nmol/L is based on a reference range, not on clinical outcomes research. The majority of research on symptoms and quality of life finds that men with testosterone below 15–18 nmol/L frequently have significant symptoms, and that many men below 12 nmol/L function well depending on SHBG, free testosterone, and individual sensitivity.

NHS vs Private TRT

NHS pathway:

• Requires two morning testosterone tests below threshold
• Must demonstrate symptoms
• GP refers to endocrinology
• Waiting list: often 6–18 months
• Treatment options are typically limited to testosterone undecanoate injections (Nebido, every 10–14 weeks) or testosterone gel (Testogel, Tostran)
• SHBG, free testosterone, and oestradiol management is often limited

Private pathway:

• Private men's health clinics (including online services) can diagnose and prescribe with shorter wait times
• More likely to measure full panels including SHBG, free testosterone, oestradiol, prolactin
• More treatment flexibility (includes shorter-acting injectable protocols, cream formulations)
• Cost: £50–200/month depending on clinic and treatment

Online pharmacy options: Pharmacy2U provides regulated online pharmacy services in the UK, dispensing testosterone medications prescribed by authorised prescribers. For men who have a prescription and want convenient, regulated dispensing without monthly clinic visits, this is a practical option.

The Forms of TRT Available in the UK

Testosterone gels (Testogel, Tostran, Androgel):

• Applied daily to skin (shoulders, upper arms, inner thighs)
• Produces stable testosterone levels without peaks and troughs
• Easy to adjust dose
• Risk of transference to partner or children if they contact treated skin before it dries
• Most common first-line treatment in NHS and private settings

Testosterone injections:

• Testosterone undecanoate (Nebido): injected every 10–14 weeks. Produces slow, stable levels but significant peaks and troughs for some men
• Testosterone enanthate or cypionate: injected weekly or every 2 weeks. More flexible dosing, preferred by many private clinics for better hormonal stability
• Testosterone propionate: short-acting, injected every 2–3 days. More complex protocol, rarely first-line

Testosterone cream/lotion:

• Absorbed through scrotal skin, which has highest androgen receptor density
• Can produce higher DHT (dihydrotestosterone) levels than other routes
• Used in specialist private settings

Pellets (subcutaneous implants):

• Implanted under the skin every 3–6 months
• Not commonly available through NHS; used in some private settings

What Happens When You Start TRT

First 4–8 weeks:

• Energy improvements often felt within 2–4 weeks
• Libido improvement: variable, some men notice quickly, others take longer
• Mood stabilisation: typically 4–6 weeks
• Some initial fluid retention as oestradiol adjusts

Months 2–6:

• Muscle mass changes become noticeable (requires consistent training)
• Body composition improvements
• Haematocrit (red blood cell concentration) begins to rise - monitoring required
• Oestradiol may require management if aromatisation is high

Long term:

• Testicular atrophy occurs as the body's natural production suppresses in response to exogenous testosterone. This is expected and reversible on cessation. hCG (human chorionic gonadotropin) can be co-prescribed to maintain testicular volume and preserve fertility if needed.

Monitoring on TRT

Regular monitoring is not optional - it's essential. Every 3 months for the first year, then every 6 months:

• Testosterone (target range 15–25 nmol/L for most men)
• Oestradiol (should remain below 150–160 pmol/L on TRT to avoid side effects)
• Haematocrit and haemoglobin (flag if haematocrit exceeds 52–54%)
• PSA (prostate-specific antigen) - annual in men over 40 on TRT
• Full blood count
• SHBG and free testosterone

Who Should Consider TRT

TRT is appropriate for men with:

• Two confirmed morning testosterone readings below 12 nmol/L (NHS threshold) or below 15 nmol/L with significant symptoms (private threshold)
• Symptoms: persistent fatigue, significantly reduced libido, loss of morning erections, reduced muscle mass despite training, mood changes, cognitive fog
• Causes that cannot be reversed through lifestyle optimisation alone (testicular failure, secondary hypogonadism from non-reversible pituitary issues, etc.)

TRT is NOT appropriate for:

• Men with normal testosterone who want athletic performance enhancement
• Men who haven't optimised sleep, body composition, vitamin D, and stress first - many men who think they need TRT will see significant testosterone improvement from these
• Men with untreated sleep apnoea (treat the apnoea first - it suppresses testosterone severely and correcting it often brings testosterone back to normal)
• Men with active prostate cancer (absolute contraindication)

The right path before considering TRT: comprehensive blood testing to understand the full picture, optimise all lifestyle factors for 3–6 months, retest, and then make an informed decision with a qualified clinician.

Pharmacy2U - regulated UK online pharmacy for prescription medications →

---

This article is for educational purposes only. TRT is a prescription medication requiring medical assessment and ongoing clinical monitoring. Do not self-medicate with testosterone or purchase testosterone without a prescription from an authorised UK prescriber.