If you’re considering testosterone replacement therapy, you’ve probably already read plenty of opinions online. Some sources make TRT sound like a miracle cure. Others paint it as a dangerous gamble. The truth, as is usually the case in medicine, sits somewhere in the middle, and it depends enormously on your individual circumstances.
This article offers a straightforward, evidence-based look at the genuine benefits and real risks of TRT. No hype. No scare tactics. Just the information you need to have an informed conversation with your doctor.
Because here’s what matters: TRT can be genuinely life-changing for the right person, and genuinely unnecessary or even harmful for the wrong one. Understanding which category you fall into is the single most important step you can take.
The Pros: What TRT Can Actually Do
Restored Energy and Reduced Fatigue
This is often the benefit men notice first and value most. The fatigue associated with low testosterone isn’t ordinary tiredness. It’s a bone-deep exhaustion that doesn’t respond to more sleep, more coffee, or more willpower. Men describe it as feeling like they’re wading through treacle, or like someone has turned their internal dimmer switch down to 30%.
When testosterone levels are restored to a healthy range, most men report a significant improvement in energy within the first few weeks. This isn’t a stimulant-like buzz. It’s more like the fog lifting. You wake up and actually feel awake. Tasks that felt overwhelming become manageable again. The afternoons stop feeling like a wall you have to climb over.
Research published in the Journal of Clinical Endocrinology & Metabolism consistently shows that men with documented low testosterone who receive TRT report significant improvements in energy and vitality compared to placebo groups.
Improved Mood and Mental Health
Low testosterone and depression share a complicated relationship. They often coexist, and each can make the other worse. Many men with low testosterone experience irritability, low mood, anxiety, and a general sense of emotional flatness that they struggle to explain. Some have been prescribed antidepressants when the underlying issue was hormonal.
TRT isn’t an antidepressant, and it shouldn’t be presented as one. But for men whose mood symptoms are driven by genuine testosterone deficiency, restoring normal levels often produces a meaningful improvement. Men frequently describe feeling more emotionally resilient, more like themselves, and more able to engage with life.
That said, if you have a diagnosis of clinical depression, TRT alone is unlikely to resolve it. Testosterone deficiency may be a contributing factor, but mental health is multifaceted, and treatment should address all relevant dimensions.
Restored Libido and Sexual Function
This is one of the most well-documented benefits of TRT. Testosterone plays a central role in male sexual desire, and low levels frequently result in reduced libido, difficulty achieving or maintaining erections, and diminished sexual satisfaction. These issues can place enormous strain on relationships and self-esteem.
For men with documented low testosterone, TRT typically restores sexual desire and can improve erectile function, though it’s important to note that erectile dysfunction has many potential causes. If your ED is primarily vascular or neurological, testosterone alone may not fully resolve it, though it can still help when used alongside other treatments.
Body Composition Changes
Testosterone influences how your body distributes fat and builds muscle. Men with low testosterone tend to accumulate visceral fat (the metabolically dangerous fat around the organs) and find it increasingly difficult to maintain or build muscle mass, even when exercising regularly.
With TRT, many men experience a gradual shift in body composition: reduced fat mass and increased lean muscle mass. This isn’t automatic. You still need to exercise and eat well. But testosterone removes the hormonal barrier that was making those efforts feel futile. Men who felt like their body had stopped responding to the gym often find that their efforts start producing results again.
These changes are typically gradual, becoming noticeable over 3-6 months and continuing to improve over the first year of treatment.
Improved Bone Density
Testosterone plays an important role in maintaining bone density, and men with low testosterone are at increased risk of osteoporosis and fractures. TRT has been shown to improve bone mineral density, particularly in the spine and hip. This is a benefit that you won’t feel day to day, but it has significant implications for long-term health, especially as you age.
Cognitive Function
“Brain fog” is one of the most frustrating symptoms of low testosterone. Men describe difficulty concentrating, slower mental processing, trouble finding words, and a general sense that their mind isn’t as sharp as it used to be. While the research on testosterone and cognition is still evolving, many men on TRT report subjective improvements in mental clarity and focus.
The Cons: What You Need to Know
Impact on Fertility
This is arguably the most significant downside of TRT, and one that isn’t discussed enough. Exogenous testosterone suppresses the hormones (LH and FSH) that drive sperm production. For many men on TRT, sperm counts can drop to zero or near-zero. This effect is usually reversible upon stopping treatment, but recovery can take months to over a year, and in some cases, full recovery may not occur.
If you’re planning to have children, or if there’s any possibility you might want to in the future, this must be part of the conversation before you start TRT. There are alternatives, such as clomiphene citrate or hCG, that can raise testosterone while preserving fertility. A responsible clinician will always discuss this with you before prescribing.
Polycythaemia (Elevated Red Blood Cells)
Testosterone stimulates erythropoiesis, the production of red blood cells. While a modest increase can be beneficial (it’s one reason energy improves), excessive red blood cell production, a condition called polycythaemia, can thicken the blood and increase the risk of blood clots, stroke, and other cardiovascular events.
This is why regular blood tests monitoring haematocrit and haemoglobin levels are non-negotiable on TRT. If levels climb too high, your dose may need adjusting, or you may need to donate blood to bring levels down. The NHS describes polycythaemia as a condition requiring medical management, and it’s one of the key reasons TRT should never be self-administered without monitoring.
Skin Reactions and Acne
Testosterone can stimulate sebaceous glands, leading to oilier skin and, in some men, acne. This is usually mild and manageable, but for some men, particularly those who were acne-prone in their younger years, it can be a genuine nuisance. Topical treatments and dose adjustments usually help. If you’re using testosterone gel, you may also experience skin irritation at the application site.
It’s a Long-Term Commitment
TRT is not a short course of treatment. For most men, it’s a lifelong commitment. Once you start, your body’s own testosterone production is suppressed, and stopping treatment will result in a period of very low testosterone while your natural production (slowly) recovers, if it recovers fully at all.
This isn’t necessarily a con if you genuinely need TRT, any more than insulin is a “con” for someone with diabetes. But it’s something you need to go into with your eyes open. You’ll need regular blood tests, ongoing prescriptions, and a relationship with a clinician who can manage your treatment over years and decades.
Oestrogen-Related Side Effects
Testosterone can be converted to oestradiol (a form of oestrogen) by an enzyme called aromatase. If oestrogen levels rise too high, men can experience side effects including water retention, mood changes, and in rare cases, gynaecomastia (breast tissue development). This is manageable with dose adjustments and, if necessary, medication, but it requires monitoring.
Testicular Atrophy
Because TRT suppresses the signals that drive testicular function, the testes may shrink in size over time. This is a cosmetic concern for some men and is related to the fertility impact discussed above. It’s reversible if TRT is discontinued, and can be mitigated with hCG therapy if desired.
Cost (If Going Private)
While TRT is available on the NHS, many men opt for private treatment for faster access and more treatment options. Private TRT in the UK can cost between 50 and 150 pounds per month for medication, plus blood tests and consultations. Over years, this adds up to a significant financial commitment. It’s worth weighing this against the quality-of-life improvements you’re likely to experience.
Who Benefits Most from TRT?
The evidence is clearest for men who have:
- Confirmed low testosterone on at least two morning blood tests (total testosterone below 8 nmol/L, or between 8-12 nmol/L with significant symptoms)
- Genuine symptoms that are consistent with testosterone deficiency, not just one or two vague complaints
- No reversible underlying cause, or where the underlying cause has been addressed and levels remain low
- No contraindications such as active prostate cancer, untreated severe sleep apnoea, or a desire for near-term fertility
Men who tend to get the most dramatic benefit are those who have been symptomatic for a long time, whose levels are clearly low, and who have been struggling despite making lifestyle improvements. For these men, TRT often feels like having a missing piece restored.
Who Should Think Carefully Before Starting TRT?
TRT may not be the right choice if:
- Your testosterone is borderline. If your levels are in the grey zone (8-12 nmol/L), it’s worth exploring whether lifestyle changes, improved sleep, weight loss, or stress management could raise your levels naturally first.
- You want to have children. Discuss fertility-preserving alternatives with your doctor before committing to TRT.
- Your symptoms might have other causes. Depression, sleep apnoea, thyroid disorders, and chronic illness can all produce symptoms that overlap with low testosterone. A thorough medical workup is essential.
- You’re expecting a magic bullet. TRT restores a hormone. It doesn’t fix poor sleep habits, a bad diet, chronic stress, or relationship problems. It works best as part of a holistic approach to health.
Making an Informed Decision
The decision to start TRT is personal, and it should be made with full knowledge of both the benefits and the trade-offs. Here’s a practical framework for thinking it through:
- Get properly tested. Don’t rely on symptoms alone. Get a comprehensive blood panel including total testosterone, free testosterone, SHBG, LH, FSH, oestradiol, prolactin, thyroid function, and a full blood count. Morning blood draws are essential, as testosterone levels are highest in the morning.
- Address reversible factors first. If you’re overweight, sleeping badly, or highly stressed, tackle these first. You may find your levels improve without medication. The NICE guidelines on testosterone deficiency recommend addressing modifiable risk factors as a first step.
- Consult a specialist. Not all GPs are well-versed in testosterone management. An endocrinologist or a specialist TRT provider will give you more nuanced guidance.
- Understand the commitment. If you start, plan to continue. Make sure you’re comfortable with the monitoring requirements and, if going private, the ongoing costs.
- Choose a regulated provider. Whether NHS or private, ensure your care is provided by qualified medical professionals with proper regulatory oversight.
Frequently Asked Questions
Is TRT worth it if my testosterone is borderline?
If your levels are between 8-12 nmol/L, the decision is less clear-cut than if your levels are very low. Some men in this range experience significant symptoms and benefit from TRT, while others may improve with lifestyle changes alone. The best approach is to trial lifestyle modifications first, including weight management, improved sleep, stress reduction, and exercise, and retest after 3-6 months. If levels and symptoms haven’t improved, TRT may be warranted. A knowledgeable clinician can help you weigh the options based on your full clinical picture.
Will TRT make me aggressive?
The idea that testosterone makes men aggressive is largely a myth when we’re talking about physiological replacement doses. TRT aims to restore normal levels, not push them to supraphysiological extremes. Most men on properly managed TRT report improved mood stability, not increased aggression. If anything, the irritability associated with low testosterone often improves on treatment. The “roid rage” stereotype comes from anabolic steroid abuse at doses many times higher than medical TRT.
Can I take TRT and still have children?
Not easily while on standard TRT, as it suppresses sperm production. However, there are strategies to manage this. Some men use hCG alongside TRT to maintain testicular function and some degree of fertility. Others use alternatives like clomiphene citrate that raise testosterone through a different mechanism. If fertility is a concern, you must discuss this with your doctor before starting treatment. Switching to a fertility-preserving protocol before trying to conceive is also an option, though it requires planning.
How quickly will I see results from TRT?
Improvements in energy and mood often begin within 2-4 weeks. Libido typically improves within 4-8 weeks. Body composition changes, such as reduced fat and increased muscle, are more gradual, usually becoming noticeable around 3-6 months. Maximum benefits are generally seen at 12-18 months. The timeline varies between individuals based on starting testosterone levels, the type of TRT used, lifestyle factors, and individual physiology.
Does TRT cause hair loss?
TRT can accelerate male pattern baldness in men who are genetically predisposed to it. Testosterone is converted to dihydrotestosterone (DHT) in the body, and DHT is the primary driver of androgenetic alopecia. If you’re already experiencing some hair thinning, TRT may speed this process. However, if you’re not genetically predisposed to hair loss, TRT is unlikely to cause it. Treatments like finasteride can help manage DHT-related hair loss, though they carry their own considerations that should be discussed with your doctor.
Where to Go from Here
If you’ve weighed the pros and cons and feel that TRT might be right for you, the next step is getting a proper assessment. This means comprehensive blood work, a thorough medical history, and a conversation with a clinician who specialises in hormone management.
At Evernu, we’re a RQIA-regulated healthcare provider offering medically supervised testosterone treatment across the UK. Our approach is built on thorough diagnostics, honest conversations about risks and benefits, and ongoing monitoring to ensure your treatment is both safe and effective. We don’t prescribe TRT to men who don’t need it, because the goal isn’t to sell a treatment. It’s to help men who are genuinely struggling get the medical care they deserve.
If you’ve been living with the symptoms of low testosterone and you’re ready to find out whether TRT could help, learn more about our testosterone treatment service.
This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any new treatment.
Reviewed by the Evernu medical team. Last updated: March 2026.
