TRT and Fertility: What Men Need to Know Before Starting Treatment

Quick Facts:

• TRT can significantly reduce sperm production.
• External testosterone suppresses LH and FSH, the hormones responsible for stimulating testosterone and sperm production within the testes.
• Normal testosterone levels don’t guarantee normal fertility.
• You can have excellent circulating testosterone levels on TRT while sperm production is substantially reduced.
• TRT is not contraception. Some men continue producing sperm and can conceive while receiving testosterone treatment.
• Fertility should be considered before starting TRT.
• A baseline semen analysis can help establish sperm concentration, motility and morphology before treatment.
• There may be alternative treatment approaches. Depending on the individual’s circumstances, specialist treatment may involve hCG, FSH or selective oestrogen receptor modulators (SERMs).
• Sperm production may recover after stopping TRT, but recovery isn’t guaranteed. The process can take months and, in some cases, considerably longer.

Why Does TRT Affect Fertility?

This comes down to how the body’s hormonal system works.

Normally, the brain and testes communicate through the hypothalamic-pituitary-gonadal axis (HPG axis, also referred to as the HPTA).

The hypothalamus produces GnRH, which stimulates the pituitary gland to produce two important hormones:

• LH (Luteinising Hormone) stimulates the Leydig cells in the testes to produce testosterone.

• FSH (Follicle-Stimulating Hormone) acts primarily on Sertoli cells within the testes and plays an important role in sperm production.

When you introduce testosterone from outside the body, the brain detects that there is now plenty of testosterone circulating. As a result, it reduces the hormonal signals coming from the hypothalamus and pituitary: LH and FSH fall.

And when LH and FSH fall, the testes receive much less stimulation. In simple terms, the brain stops telling the testes to do anything!

This is why testicular volume can decrease during TRT and why sperm production can fall substantially.

The important point is that the testosterone circulating in your bloodstream isn’t the same thing as the testosterone environment required inside the testes to produce sperm.

You can therefore have an excellent testosterone level on TRT while your sperm production is simultaneously falling.

TRT Is Not Contraception

Studies of testosterone administration have demonstrated substantial suppression of sperm production in many men, and testosterone has even been investigated as a potential male contraceptive.

But this does not mean TRT should be relied upon as contraception.

The response is variable.

Some men continue to produce measurable sperm and can, and do, conceive on TRT.

How quickly sperm production falls, how low it gets and how quickly it recovers after stopping testosterone varies between individuals.

So if you are taking TRT and don’t want a pregnancy, you still need appropriate contraception.

Conversely, if you do want a pregnancy, assuming that your testosterone treatment is not affecting your fertility would be a mistake.

Should You Check Fertility Before Starting TRT?

If future fertility matters to you, I think this is an important conversation to have before treatment begins.

One reason is obvious: if you know what your sperm count looks like before TRT, you have a useful baseline.

But there is another reason that is often overlooked.

Low testosterone and impaired fertility can coexist.

A man may present with symptoms of testosterone deficiency and discover that he also has an underlying problem affecting sperm production.

That could be related to the same underlying dysfunction affecting testosterone production, previous testicular injury or surgery, varicocele, medication, illness or a number of other factors.

And this matters because fertility is already a moving target.

Male sperm counts have declined substantially in population studies over recent decades, although the reasons are complex and likely multifactorial.

So if having children in the future is important to you, it is worth establishing where you stand before introducing a treatment that can further suppress sperm production.

A semen analysis can provide useful information about sperm concentration, motility and morphology before treatment.

It doesn’t guarantee future fertility, and one semen analysis isn’t necessarily the final word, but it can be a valuable baseline.

So What Are Your Options If You Have Low Testosterone but Want Children?

There isn’t one answer for every man.

The right approach depends on why testosterone is low, how severe the symptoms are, whether fertility is an immediate or future priority, and what your semen analysis and hormonal profile show.

There are several potential strategies.

1. Delay TRT

Sometimes the simplest option is to address fertility first.

If having a child is an immediate priority, starting TRT may not make sense.

This is one reason why men who are concerned about fertility may not be offered conventional TRT through NHS services. Instead, the focus may be on investigating the cause of low testosterone and using fertility-preserving or fertility-directed treatment where appropriate.

That doesn’t mean the symptoms of low testosterone aren’t real, it means the treatment needs to take the man’s reproductive goals into account.

This decision has an obvious major drawback: your low testosterone symptoms may remain inadequately addressed while you are trying to conceive, although alternative treatment approaches may be appropriate depending on the underlying cause.

2. hCG

Human chorionic gonadotrophin, or hCG, is particularly interesting because it acts in a similar way to LH.

Remember that LH normally tells the testes to produce testosterone.

This means that, rather than simply supplying testosterone from outside the body, hCG can provide a signal to the testes themselves.

In fertility treatment, this can help restore or maintain the testosterone environment within the testes that is important for sperm production.

hCG therefore has a legitimate role in men who are actively trying to conceive.

Solo, relatively high-dose hCG therapy is sometimes used to both treat low testosterone and avoid switching off sperm production.

In practice, this is not a method I would often advise.

My favoured use of hCG is alongside TRT to stimulate some testicular action. The hope is that you can maintain the use of TRT and hence feel well, and use the hCG to stimulate, promote or maintain some sperm production.

However, using hCG alongside TRT does not guarantee that sperm production or fertility will be preserved, and evidence supporting this approach remains limited. This is particularly important for men actively trying to conceive, where specialist fertility assessment should guide treatment.

3. hCG Plus Recombinant FSH

If sperm production needs more stimulation, hCG may be combined with recombinant FSH (rFSH).

This makes physiological sense: hCG provides LH-like stimulation to the Leydig cells and helps restore intratesticular testosterone. FSH acts on the Sertoli cells, which are directly involved in supporting sperm development.

This is the regimen, in fact, I used for my own fertility protocol for our third child. I was on solo TRT and added in hCG alongside rFSH.

Within four months, pregnancy was achieved!

These are specialist treatment protocols, usually tailored around the individual’s reproductive goals and monitored appropriately.

Of course, my own experience is not a guarantee that the same approach will work for every man.

4. What About SERMs?

Selective oestrogen receptor modulators, or SERMs, such as clomiphene or enclomiphene, are another potential option used in some men, particularly those with secondary hypogonadism who wish to preserve fertility.

Rather than supplying testosterone from outside the body, they work by altering oestrogen feedback at the level of the hypothalamus and pituitary.

This can increase GnRH, LH and FSH signalling and, in some men, increase their own testosterone production while maintaining testicular function.

That can make them attractive when fertility is a priority.

However, they aren’t a perfect solution.

Response varies between men, they aren’t universally licensed or used for male hypogonadism in every setting, and they can produce adverse effects.

There is also a fundamental difference between using a SERM to stimulate your own testosterone production and using TRT to replace testosterone that your body isn’t adequately producing.

What If You Are Already on TRT?

Don’t panic.

If conception becomes a priority, the appropriate approach is to discuss this early with a doctor experienced in male fertility and reproductive endocrinology.

Depending on the circumstances, treatment may involve stopping testosterone or a fertility protocol with agents such as hCG and, where indicated, FSH.

The timeline can be months rather than weeks because sperm production itself takes time.

And this is exactly why fertility should ideally be discussed before TRT starts.

The Bottom Line

TRT can be life-changing for the right man.

But fertility is one of the areas where you really do need to think several steps ahead.

If you might want children in the future, don’t simply start TRT and worry about fertility later.

Ask the question beforehand.

Is my family complete?

If the answer is no, or even “I’m not sure”, fertility should form part of the initial assessment.

That may mean checking a baseline semen analysis, investigating the underlying cause of low testosterone and considering whether fertility-preserving or fertility-directed treatment is more appropriate.

Because TRT isn’t simply replacing a number on a blood test, it changes the hormonal signals controlling the testes.

And if having children matters to you, that needs to be part of the treatment decision from day one.

FAQS

Can you have children while taking TRT?

Yes, pregnancy is still possible while a man is receiving TRT.

However, testosterone treatment can substantially suppress sperm production, sometimes to the point where no sperm are detected in the ejaculate. TRT should therefore not be relied upon as contraception, nor should fertility be assumed to be unaffected.

Does TRT permanently affect fertility?

Not necessarily.

Many men experience a recovery in sperm production after stopping testosterone, although the timeline varies. Recovery may take several months or longer, and some men may not return to their previous sperm production levels.

Can hCG preserve fertility while on TRT?

hCG can stimulate testosterone production within the testes and may help maintain some testicular function during TRT.

However, this does not guarantee preserved sperm production or fertility. Men wishing to conceive should seek specialist advice rather than relying on hCG alongside testosterone treatment.

Should you have a semen analysis before starting TRT?

If you are considering having children in the future, a baseline semen analysis is worth discussing before treatment begins.

It provides information about sperm concentration, motility and morphology, helping identify potential fertility concerns before introducing testosterone therapy.