Testosterone Replacement Therapy (TRT): What Every Man Should Know Before Starting

Low testosterone, blood tests, fertility, benefits, risks and the questions worth asking before beginning treatment.

I want to start with a question.

If your testosterone results came back low tomorrow, would you know what to do next?

Perhaps you've been feeling unusually tired. Your sex drive isn't what it used to be. You're struggling to maintain muscle, your recovery seems slower, or your erections have become less reliable.

You've heard about testosterone replacement therapy. Perhaps a friend has started treatment and speaks highly of the difference it's made.

And now you're wondering whether TRT might be the answer for you.

It's a reasonable question.

But I want to suggest that there's an even more important question worth asking first.

Why is your testosterone low?

Because the answer matters enormously.

It determines whether testosterone replacement is an appropriate treatment, whether there are other health conditions that require attention, and whether meaningful changes to your lifestyle might improve your hormonal health.

In my previous article, What's Really Happening to Men After 40?, I encouraged men to look under the hood before assuming that every change in energy, strength or sexual function is simply a testosterone problem.

This article continues that conversation.

We're going to look at what TRT actually does, how testosterone deficiency should be investigated, what treatment can realistically improve, and what every man deserves to understand before making a decision.

Hormonal disorders and prescription treatments require assessment by qualified medical professionals. My role here is to help you approach those conversations with knowledge, confidence and a clear understanding of the lifestyle factors that influence your health.

And I believe that is a very worthwhile place to start.

What exactly is testosterone replacement therapy?

Testosterone is one of the principal hormones involved in men's physical and reproductive health.

It contributes to sexual desire, muscle and bone maintenance, red blood cell production and a range of other physiological processes.

Most testosterone is produced by the testes, under the direction of hormonal signals originating in the brain.

When that system isn't functioning adequately, testosterone levels may become abnormally low.

Testosterone replacement therapy, commonly called TRT, involves prescribing testosterone to restore levels to an appropriate physiological range in men with clinically diagnosed testosterone deficiency.

Treatment may be delivered through injections, gels applied to the skin or other formulations, depending on availability and individual circumstances.

The medical objective is to correct a deficiency and improve the symptoms associated with it.

This is an important distinction.

Medical testosterone replacement is different from using excessive doses of anabolic steroids for muscle growth or athletic performance.

TRT is intended to restore normal function where a genuine deficiency exists.

And like any medical intervention, its value depends on whether we're treating the right condition in the right person.

How do you know whether your testosterone is actually low?

Let's consider the symptoms that commonly lead men to request testosterone testing.

Fatigue. Reduced libido. Erection difficulties. Changes in mood. Less motivation. Loss of muscle. Increased abdominal fat.

These experiences can understandably raise questions about hormonal health.

But here's something I want you to appreciate.

Many of these symptoms are not exclusive to low testosterone.

Persistent tiredness can have several explanations, including poor sleep, anaemia, thyroid conditions, depression, medication effects and other medical problems.

Changes in sexual desire can involve hormones, but they may also be influenced by stress, relationships, physical health and psychological wellbeing.

Difficulty maintaining an erection can sometimes involve testosterone. It can also involve circulation, blood pressure, diabetes, medications, nerves and other factors.

So we cannot reliably diagnose testosterone deficiency from symptoms alone.

According to the Endocrine Society's July 2026 statement on testosterone replacement therapy, a diagnosis requires compatible symptoms together with consistently low testosterone levels confirmed through appropriate testing.

And that word consistently is important.

Understanding your testosterone test ranges

South African laboratories commonly report total testosterone in nmol/L; international sources may use ng/dL.

A large reference-range study found the following in healthy, non-obese men aged 19–39:

• Reference range: approximately 9.2–31.8 nmol/L (264–916 ng/dL).
• Average: approximately 19.1 nmol/L (550 ng/dL).

Laboratory ranges vary. These are population figures and not personal treatment targets.

Men differ considerably. Age groups overlap: an older man can have higher testosterone than a younger man. Health, body fat, sleep, medication and testing conditions all influence results.

A “normal” total testosterone result deserves further investigation if symptoms persist, particularly when SHBG (sex hormone-binding globulin) affects free testosterone. Two men with similar results may feel very different. Your previous levels purpose is to provide some context, but a fall from a naturally higher level alone does not establish a need for TRT.

The European Association of Urology uses approximately 12 nmol/L when assessing symptomatic men; guidelines differ, and diagnosis requires clinical assessment and repeated testing.

If TRT is indicated, finding the right treatment is a process. Work with an endocrinologist or urologist experienced in testosterone treatment. Repeated, appropriately timed blood tests, symptom reviews and safety checks help refine your regimen over time. The aim is meaningful improvement within an appropriate physiological range. More testosterone is not automatically better.

This individualised approach is reflected in Endocrine Society guidance and the AUA's treatment and monitoring recommendations.

Why are two testosterone tests important?

Testosterone levels vary naturally throughout the day and can also be affected by illness and other circumstances.

This is why professional guidance generally recommends obtaining at least two separate early-morning testosterone measurements, usually while fasting, before diagnosing testosterone deficiency.

Testing conditions may need to be adjusted for men with unusual sleep schedules or other relevant circumstances.

One result tells us what your testosterone was at a particular moment.

Repeated measurements help establish whether a genuine deficiency exists.

And sometimes, even those results lead to further questions.

Total testosterone, free testosterone and SHBG

Most testosterone circulating in your blood is attached to proteins.

One of these is called sex hormone-binding globulin, or SHBG.

A smaller proportion circulates without being bound to those proteins, referred to as free testosterone.

Changes in SHBG can affect how total testosterone results should be interpreted.

Depending on your circumstances, your doctor may assess SHBG and calculate free testosterone to gain a more complete picture.

Other useful hormones include LH and FSH, which help regulate the testes.

Measuring these can assist your doctor in identifying whether the testosterone deficiency originates primarily in the testes or in the hormonal signalling system.

Further investigations may be appropriate depending on the findings.

And this brings us to the question I consider particularly important.

Before treating low testosterone, investigate WHY it's low

A low testosterone result is useful.

But understanding your levels underlying cause helps determine the most appropriate response.

Broadly speaking, testosterone deficiency may result from conditions affecting the testes, disorders involving hormonal signals from the brain, or other health factors that influence testosterone production.

Some causes are permanent.

Others may be potentially reversible.

1. Excess body fat and metabolic health

Excess body fat, particularly in men living with obesity, is associated with lower testosterone levels in some circumstances.

Hormonal regulation is influenced by several interconnected aspects of metabolic health.

Research has shown that significant weight loss can improve testosterone concentrations in some men.

The Endocrine Society's 2026 statement identifies weight loss as the usual first-line approach for men whose testosterone deficiency is associated with overweight or obesity and who have no other identified cause.

It means improving body composition may be part of treating the underlying problem, rather than simply addressing a number on a blood test.

I shared Ignus's experience in our previous article.

At 40, he was carrying considerable excess weight, had low testosterone results and was considering TRT.

With his doctor's involvement, we began addressing his nutrition, physical activity, body composition and daily habits.

Over 12 weeks, he lost 27kg.

When his blood work was repeated, his testosterone had improved substantially.

His experience was remarkable.

But what I value most about his story isn't simply the change in the laboratory result.

It's that he took the time to understand his health and act on the areas he could influence.

That's the thinking I want to encourage.

2. Sleep and recovery

Sleep plays an important role in hormonal regulation and overall health.

If you're consistently sleeping poorly, waking exhausted or struggling with recovery, that deserves investigation.

Sleep apnoea is particularly important to consider in men who snore heavily, experience interrupted breathing during sleep or remain unusually tired despite spending sufficient time in bed.

Addressing sleep problems can improve health and wellbeing, regardless of whether testosterone levels change.

And if you're working long hours, training hard and continually sacrificing sleep, adding another intervention without considering recovery may leave a significant part of the problem untouched.

3. Nutrition, exercise and physical stress

Your body needs adequate energy and nutrients to function properly.

Severe calorie restriction, inadequate nutrition and substantial physical stress can affect reproductive hormone regulation in some men.

This becomes particularly relevant when a man is training intensively, dieting aggressively and struggling to recover.

Physical training is valuable.

But more training isn't automatically better training.

And eating less isn't automatically better nutrition.

Good coaching involves understanding the demands placed on a man's body and developing a programme that supports both progress and recovery.

4. Medication and other medical conditions

Certain prescription medications, including opioids and corticosteroids, may affect testosterone production.

Other possible contributors include thyroid conditions, significant illnesses, testicular disorders and conditions involving the pituitary gland.

Some of these require specialist assessment and specific treatment.

Never change or discontinue prescribed medication without discussing it with your doctor.

The important point is that different causes of low testosterone require different responses.

That's precisely why a proper investigation matters.

When is testosterone replacement therapy the right treatment?

There are men whose bodies cannot produce adequate testosterone because of genuine medical conditions affecting the testes or hormonal signalling system.

For these men, TRT can be an important and effective treatment.

And in some circumstances, treatment may need to continue long term.

When a permanent deficiency exists, improving sleep, body composition and nutrition remains valuable, but those changes may not restore adequate natural testosterone production.

Conversely, when a man's testosterone is low in association with potentially reversible factors, addressing those factors may be an important part of the initial treatment plan.

The appropriate decision depends on the underlying diagnosis, symptoms, individual risks and clinical judgement.

The goal is to treat the man and the condition—not simply the laboratory number.

What improvements can you realistically expect from TRT?

Once treatment is medically indicated, it's important to understand what it may improve.

There are genuine benefits.

But we also need realistic expectations.

Sexual desire and erectile function

For men with confirmed testosterone deficiency, replacement therapy can improve sexual desire and some aspects of sexual function.

In the Testosterone Trials, published in the New England Journal of Medicine, older men with low testosterone experienced improvements in sexual activity, desire and erectile function with treatment.

These improvements were meaningful, although generally modest.

Importantly, testosterone is not the only factor involved in achieving and maintaining erections.

Blood flow, nerve function, cardiovascular health, medication, psychological wellbeing and relationships all play a part.

TRT may help when testosterone deficiency contributes to the problem, but it won't necessarily resolve erectile difficulties caused by other conditions.

I want men to understand that distinction, particularly because changes in sexual function can sometimes reveal important information about cardiovascular and metabolic health.

We'll explore this subject in greater depth in our upcoming article on sex and sexual health after 40.

Muscle mass and body composition

Testosterone supports muscle and bone health.

Appropriate replacement therapy can improve lean mass and may reduce fat mass in men with testosterone deficiency.

But good body composition and strength still depend heavily on training, nutrition, physical activity and recovery.

This is something I feel strongly about after more than 16 years of working in physical transformation.

Your muscles still need a reason to become stronger.

Progressive resistance training remains valuable.

So does adequate protein, appropriate calorie intake, cardiovascular fitness and proper recovery.

Whether you're receiving testosterone replacement therapy or not, these fundamentals deserve attention.

Energy, mood and general wellbeing

Some men experience meaningful improvements in energy, mood and wellbeing after beginning treatment.

Others notice more limited changes.

The clinical evidence is less consistent for general fatigue and vitality than it is for certain aspects of sexual function.

In the Testosterone Trials, treatment improved several measures of sexual function but did not significantly improve the primary vitality outcome.

This reminds us why proper assessment is so important.

If your exhaustion has several contributing causes, correcting testosterone alone may not resolve everything you're experiencing.

A better hormone result and better overall health are related goals, but they aren't always the same thing.

Fertility: an important conversation before starting TRT

I want to give this subject the attention it deserves.

If you're considering TRT and may want to have children, fertility should be discussed before treatment begins.

Testosterone supplied from outside the body reduces the hormonal signals that normally stimulate natural testosterone and sperm production.

As a result, TRT can substantially suppress sperm production.

In some men, sperm production may stop during treatment.

Recovery after discontinuing testosterone is possible, but the time required varies, and complete recovery cannot be guaranteed in every case.

For men who want to preserve fertility, specialist assessment is particularly important.

Depending on the underlying cause, other medical approaches may be considered.

The American Urological Association and American Society for Reproductive Medicine's male infertility guidance advises against prescribing external testosterone to men interested in current or future fertility.

This isn't a small consideration.

Having children—or choosing to keep that possibility open—is a deeply personal decision.

You deserve to understand how treatment may affect that choice before beginning.

Understanding the different TRT treatments

Testosterone replacement is available in several forms, including injections and gels.

Availability, approved formulations and costs differ by country and individual circumstances.

Testosterone injections

Injectable preparations deliver testosterone at intervals determined by the medication and treatment plan.

Some are administered more frequently, while others are longer-acting.

Depending on the formulation and schedule, testosterone concentrations may fluctuate between doses.

Your doctor should explain the practical implications, including how treatment is administered and when follow-up blood tests should be taken.

Testosterone gels

Testosterone gels are applied to the skin, usually daily, according to the product instructions.

They may provide relatively consistent hormone delivery for some men.

However, correct application matters, including precautions to prevent accidental transfer to partners, children or others through skin contact.

Neither option is automatically superior for every man.

A suitable treatment should account for medical considerations, practical preferences, cost, tolerability and the ability to monitor therapy appropriately.

And the objective remains the same: restoring testosterone to an appropriate physiological range.

What are the risks of TRT?

A responsible decision involves understanding the benefits and potential risks of treatment.

TRT can increase the concentration of red blood cells, measured through haematocrit.

If haematocrit rises excessively, treatment may need to be adjusted or interrupted under medical supervision.

Blood pressure and cardiovascular health also deserve attention.

What does the cardiovascular research tell us?

The large TRAVERSE trial, published in 2023, studied more than 5,200 middle-aged and older men with confirmed testosterone deficiency and existing or elevated cardiovascular risk.

The primary measure of major cardiovascular events occurred in:

• 7.0% of men receiving testosterone

• 7.3% of men receiving placebo

Within the study's follow-up period, testosterone treatment was not associated with a higher rate of the primary cardiovascular outcome.

That was an important and reassuring finding.

However, the testosterone group experienced higher rates of certain other events, including atrial fibrillation, acute kidney injury and pulmonary embolism.

The US Food and Drug Administration has updated testosterone prescribing information in response to evolving evidence, including cardiovascular safety findings, blood pressure effects and prostate-related information.

So while the research has helped answer important questions, treatment still requires individual risk assessment and appropriate monitoring.

What about prostate health?

Prostate health is another important consideration.

Available clinical trials have not established that appropriately prescribed TRT causes prostate cancer, but long-term questions remain, and certain prostate conditions require particular caution.

Depending on age, medical history and individual risk, appropriate prostate assessment and monitoring may form part of treatment.

This is something your prescribing doctor should discuss with you.

Good treatment is never just about achieving a particular testosterone level. It's about improving your health while managing the risks responsibly.

What should happen before your first prescription?

I want you to think of this as a proper health consultation rather than simply an appointment to obtain testosterone.

By the time treatment is prescribed, there should be a clear understanding of your symptoms, relevant medical history and the evidence supporting your diagnosis.

Your doctor should have considered possible underlying causes and other conditions that may be influencing your health.

Before treatment, the assessment may include a full blood count and haematocrit, blood pressure, relevant metabolic health markers and prostate-related evaluation when appropriate.

Your fertility intentions should also be discussed.

And you should understand what treatment is expected to improve.

Not vague promises about feeling younger.

Specific symptoms, realistic expectations and a clear plan for reviewing your progress.

The setting of the consultation matters less than its quality.

Whether you receive care through a traditional medical practice or an appropriately managed online service, the assessment should be clinically thorough.

You deserve to know what's being treated and why.

TRT requires ongoing monitoring

Beginning testosterone treatment is not the end of the medical process.

Regular follow-up helps assess whether testosterone levels are within the intended range, whether symptoms are improving and whether treatment is causing unwanted effects.

The European Association of Urology's guidance recommends monitoring testosterone and haematocrit at approximately three, six and twelve months after starting treatment, and thereafter annually, with adjustments for individual circumstances and risk.

Other assessments may include blood pressure, relevant prostate-related monitoring and ongoing review of symptoms.

If treatment isn't providing the expected benefits, that deserves investigation too.

The objective is meaningful improvement in health and wellbeing—not simply maintaining a prescription indefinitely without reviewing its value.

Is TRT a lifelong commitment?

For some men with permanent testosterone deficiency, long-term treatment may be medically appropriate.

For others, the outlook may be different.

But there is something important to understand about stopping TRT.

Because testosterone replacement suppresses the body's natural production signals, the body may take time to recover after treatment is discontinued.

Recovery varies according to the individual, the underlying cause and treatment history.

Some men may recover natural production. Others may continue to experience deficiency and require further medical assessment or treatment.

Before beginning TRT, it's sensible to discuss what longer-term treatment might involve and what the options would be if treatment needed to change or stop.

It's much easier to make a confident decision when you understand the potential longer-term implications from the beginning.

Ten questions worth asking your doctor about TRT

If you're considering testosterone replacement therapy, these are the questions I'd encourage you to take into your consultation.

1. Have we confirmed my testosterone deficiency with appropriately timed, repeated blood tests?

2. What do my total testosterone, free testosterone and other relevant results tell us?

3. Do we understand why my testosterone is low?

4. Are there potentially reversible health or lifestyle factors worth addressing?

5. Is testosterone replacement the most appropriate treatment for my particular condition?

6. What improvements can I reasonably expect, and how will we measure them?

7. How could treatment affect my fertility or future plans to have children?

8. What risks are relevant to my medical history, and what monitoring will I need?

9. Which treatment formulation makes sense for me, and what are the ongoing practical and financial commitments?

10. If treatment doesn't help, or I eventually need to stop, what would the next steps be?

You don't need to become an expert in endocrinology.

But you should feel informed and comfortable enough to participate meaningfully in decisions about your own health.

Looking after the whole man

I want to return to something I've learnt through years of coaching.

Our bodies are remarkably capable of adapting.

They respond to the conditions we create through our nutrition, movement, training, sleep, recovery and daily habits.

And improving those conditions can make an extraordinary difference to our health and quality of life.

But there's also wisdom in recognising when a problem needs medical treatment.

I believe a strong, self-aware man can do both.

He can take responsibility for the areas of his health within his influence while respecting the knowledge and expertise of the professionals who care for him.

He can make meaningful changes to his lifestyle while accepting appropriate treatment for medical conditions.

There is no contradiction in that.

My work as a men's coach is about helping men develop the physical capacity, consistency, habits and personal ownership required to live well.

And that's why I believe the strongest approach to men's health is one that considers the whole man.

Not just his testosterone.

His body composition. Strength. Nutrition. Cardiovascular fitness. Sleep. Mental wellbeing. Relationships. Work demands. Habits and the quality of the life he's experiencing.

Because all these things matter.

And when we begin paying attention to the bigger picture, we're often in a much better position to make decisions about individual parts of our health.

What I want you to take from this

If you're concerned about your testosterone, I want you to take those concerns seriously.

Have the tests. Understand your results. Investigate the possible causes with a qualified healthcare professional.

And take an equally thoughtful look at how you're living.

The way you eat. How you train. Your body composition. Sleep. Recovery. Stress and the habits that shape your health.

There may be meaningful changes worth making.

There may also be a medical condition that requires treatment.

Understanding the difference is what matters.

You have a responsibility to yourself to care for your health with the same seriousness that you bring to the other important areas of your life.

And I believe that responsibility deserves to be approached with intelligence, self-respect and genuine care.

The objective isn't simply to have better testosterone levels.

It's to build and protect the health, strength and capacity that allow you to live a greater life.

If you'd value a mature, honest conversation before drawing conclusions about how you're feeling, book an Exploration Call with me.

We'll look at what's happening in your life right now: sleep, nutrition, training, recovery, stress and the demands you're carrying. Together, we can explore lifestyle factors that may deserve attention alongside your doctor's assessment.

We've got a lot more living to do, gentlemen.

Let's make sure we're looking after the man who's going to live it.

Jacque Visagie

MEDICAL DISCLOSURE: This article forms part of Men's Health & Vitality, a MEN | GREATER LIVES series exploring hormonal health, sexual wellbeing, physical capacity, nutrition, recovery and healthy ageing. It is provided for educational purposes and is not individual medical advice. Testosterone deficiency, laboratory results, fertility considerations and treatment decisions require assessment by qualified healthcare professionals. Do not start, change or discontinue prescribed testosterone treatment without medical guidance.