TRT, or testosterone replacement therapy, is treatment for men whose symptoms and blood tests show genuinely low testosterone. It is not a general energy booster, gym shortcut or anti-ageing treatment.
If you are feeling tired all the time, struggling with sex drive, or noticing changes in muscle and body fat, TRT may come up in your research. The important point is that those symptoms are not enough on their own. A proper diagnosis needs blood testing, repeat confirmation and clinical context.
In this guide
What the evidence actually shows
Low testosterone, sometimes called hypogonadism, can show up as low sex drive, erectile dysfunction, low mood, tiredness, loss of muscle mass or an increase in body fat. None of those symptoms are exclusive to low testosterone, which is why diagnosis relies on more than symptoms alone.
A proper diagnosis needs two things lining up. First, a morning blood test showing testosterone below the normal range. Second, that low reading should usually be confirmed on a separate occasion, because testosterone can fluctuate. Only when the blood work and symptoms point the same way does TRT usually get considered.
Before choosing a clinic, check whether it requires repeat blood testing and ongoing monitoring. A fast prescription is not useful if the diagnosis is weak.
How TRT is actually given
TRT comes in a few different forms, and the medication names are worth knowing before you decide which route might fit your life.
- Testogel and Tostran: daily gels rubbed into the skin each morning. They are a common starting point because the dose is easy to adjust.
- Sustanon 250: an injection usually given every two to four weeks, often cheaper than gels over time.
- Nebido: a longer-acting injection, typically given every ten to fourteen weeks once you are established on treatment.
- Less common options: patches, implanted pellets and nasal gels exist, but they are used far less often in the UK.
Which one suits you tends to come down to convenience, cost, monitoring results and how your body responds, rather than one form being universally better.
Pros and cons of TRT
For men with confirmed low testosterone, TRT can improve symptoms. The potential benefits include more energy, improved sex drive, better erectile function in some men, gains in muscle mass, reductions in body fat and better mood where low mood was linked to low testosterone.
The trade-offs matter too. Testosterone from outside the body can reduce sperm count and shrink the testicles over time, so fertility needs to be discussed before treatment starts. TRT can also increase red blood cell production, which is why blood monitoring is part of proper care rather than an optional add-on.
Prostate monitoring is also built into treatment. Cardiovascular risk was a concern raised by earlier research, but the largest more recent trial evidence has not found a higher rate of heart attack, stroke or cardiovascular death in men on TRT. Blood pressure can still rise on treatment, so it needs checking regularly.
Side effects to know about
- Acne or oilier skin
- Fluid retention
- Skin irritation where a gel is applied
- Breast tenderness or swelling
- Worsening of sleep apnoea in men who already have it
- Mood changes, which should be flagged to a prescriber if they happen
The safer TRT services are the ones that treat follow-up as part of the product: blood counts, testosterone levels, PSA, symptoms and side effects all need checking after treatment starts.
Who TRT is for, and who it is not for
- Suitable: men with clear symptoms plus confirmed low testosterone on blood testing, ideally on two separate readings.
- Suitable: men who have had other causes of symptoms, such as thyroid problems, depression or sleep problems, reasonably considered first.
- Needs extra care: men trying to conceive, unless fertility-preserving options are discussed.
- Not suitable: men looking for a performance or bodybuilding boost rather than treatment for diagnosed deficiency.
- Needs specialist input: men with a history of prostate cancer, breast cancer, untreated sleep apnoea, or significant heart, liver or kidney disease.
What TRT costs privately, and how the NHS route differs
Private TRT in the UK typically runs from around £99 to £150 or more a month, depending on the medication and format. Gels often sit at the higher end, while longer-acting injections can work out cheaper over a year.
The monthly fee may include medication, blood-test monitoring and clinical reviews, but not always. Extras such as fertility-preserving treatment, erectile dysfunction medication, initial consultations or extra blood tests may be priced separately, so compare the full cost rather than the headline monthly figure.
The NHS can prescribe TRT once both symptoms and blood-test criteria are clearly met, but access can take time. Men with borderline results or vague symptoms like fatigue alone may find it harder to qualify through NHS pathways. Private services can move faster, but they should still use the same diagnostic and monitoring standards.
Bottom line
TRT is a legitimate treatment for genuinely low testosterone, not a general wellness supplement. It works best when it is based on a confirmed diagnosis, a clear treatment plan and regular monitoring once treatment starts.
Medical disclaimer
This article is for general information only and is not medical advice. Testosterone replacement therapy requires blood testing, clinical assessment and ongoing monitoring by a qualified healthcare professional.
