Can Testosterone Replacement Therapy (TRT) Cause Infertility?

Testosterone replacement therapy (TRT) offers a range of benefits, but many men are unaware that it can also lead to infertility. Understanding the potential risks of this hormone therapy is critical to your success - particularly if you wish to build a family in the future.

In this article:

• What is testosterone replacement therapy (TRT)?
• How does TRT work?
• What can TRT help with?
• Forms of TRT
• Can TRT cause male infertility?
• Why does TRT reduce sperm?
• What if I have low testosterone?
• Should I freeze sperm before starting TRT?
• What if I'm already on TRT and want to restore sperm production?
• Other Potential Side Effects of TRT
• Alternative Treatments for Low Testosterone
• TRT and Sexual Function
• What You Should Know About TRT

What is testosterone replacement therapy (TRT)?

Testosterone is a hormone primarily produced in the testes in men and in smaller amounts in women’s ovaries and adrenal glands. It plays a key role in various body functions, including muscle mass, bone density, red blood cell production, and sexual function.

Testosterone replacement therapy (TRT) is a medical treatment used to increase testosterone levels in individuals with low testosterone (hypogonadism). The utilization of testosterone replacement therapy has been steadily increasing around the world, driven by growing awareness, aging populations, and increased diagnoses of hypogonadism.

How does TRT work?

Testosterone replacement therapy (TRT) helps to regulate testosterone levels by supplementing the body with synthetic or bioidentical testosterone. This helps restore levels to a normal, healthy range and re-establish hormonal balance.

What can TRT help with?

In my role as a reproductive endocrinologist, I am seeing more and more men who are utilizing testosterone replacement therapy to either increase libido (sex drive) or help increase muscle mass.

However, there are many other indications for TRT, including:

• Fatigue and low energy
• Sexual dysfunction
• Reduced muscle strength
• Mood changes, such as depression or irritability
• Difficulty concentrating or "brain fog"
• Decreased bone density (osteoporosis)

Before starting testosterone replacement therapy, always consult with a reproductive urologist in order to understand all possible side effects. Having this knowledge will help you make the most informed decision - while keeping your personal goals in mind.

Hormone Replacement Therapy for Trans Folks

In this article, we'll be focusing primarily on those who are taking testosterone replacement therapy to increase their libido and/or gain muscle mass (bodybuilding). 

However, testosterone therapy is also frequently used as part of gender-affirming care for transgender men and gender diverse people, with the goal of bringing on physical changes that better align with their gender identity, such as:

Forms of TRT

Testosterone replacement therapy is available in various forms, including injections, gels, patches, pellets, and creams. Each form has a different mechanism of action on testosterone production in the male reproductive tract.

Depending on how testosterone is administered and the dosage used, sperm counts can vary from being decreased to nonexistent.

Your reproductive urologist will help you choose the most appropriate replacement therapy based upon your own personal goals, preferences, and reproductive plans.

Can TRT cause male infertility?

The short answer? Yes, testosterone replacement therapy can cause issues with fertility. 

Many men don't realize that a decrease in sperm production is a side effect of testosterone replacement therapy, being caught off guard when they receive semen analysis results indicating a lack of sperm.

Testosterone is an androgen, a hormone produced naturally in the male testicle which is the critical hormone for spermatogenesis (sperm production).

Testosterone replacement therapy causes the body to reduce or stop its natural testosterone production due to something called a negative feedback loop, which involves the hypothalamus, pituitary, and testes.

Here's how it works:

1. The hypothalamus in the brain detects testosterone levels.
2. The brain sends signals to the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
3. These hormones stimulate cells in the testes to produce testosterone.

Why does TRT reduce sperm?

This negative feedback loop is a good thing - it's an essential regulatory system responsible for maintaining stable hormone levels throughout the body. It ensures that when sufficient levels of a hormone (like testosterone) are circulating, the body doesn't produce excess amounts.

In the case of TRT, because the body detects external testosterone as a signal that endogenous (internal) production is not needed, it suppresses the mechanisms that would normally stimulate the testes to produce more testosterone.

What you need to know:

• Testosterone replacement therapy (TRT) can lead to infertility.
• Depending on the dosage and how testosterone is administered, sperm counts can vary from being decreased to completely nonexistent.
• Even after stopping testosterone replacement therapy, it is not guaranteed that sperm production will resume (i.e. may cause permanent fertility issues).
• With this in mind, be sure to seek out a specialist who can properly counsel you and help you explore all of your options before potentially starting TRT.

What is a semen analysis?

Learn what to expect from this common test, what it can tell us about male fertility, and how its results may impact your treatment path.

What if I have low testosterone?

Men need adequate levels of testosterone to produce sperm, and with age, the production of testosterone slowly decreases. If low testosterone is an issue, other medications may be offered to help augment this.

For example, clomiphene citrate (often referred to as Clomid) is an oral medication that can be prescribed off-label to men with low testosterone. It works by stimulating the pituitary gland to increase testosterone production. 

Should I freeze sperm before starting TRT?

Some men choose to cryopreserve (freeze) multiple semen samples prior to starting testosterone replacement therapy. This strategy allows you to safeguard your current fertility prior to starting TRT.

The sperm freezing process involves the production of three separate ejaculatory samples, which then undergo semen analysis to ensure an adequate sperm count for future family building. After being analyzed by an andrologist, each sample is flash frozen (using a method called vitrification) and safely stored until you are ready to use them.

If you do become infertile after starting TRT, a reproductive endocrinologist can help you expand your family using that frozen sperm, either through intrauterine insemination (IUI) or in vitro fertilization (IVF). Both of these methods are incredibly successful in most cases.

What if I'm already on TRT and want to restore sperm production?

If you are currently utilizing testosterone placement therapy and want to try to conceive, we can refer you to one of our preferred reproductive urologists in Connecticut or New York.

These highly-trained specialists are able to offer a variety of treatments that can help most men on TRT regain sperm function and restore adequate sperm counts so they can build a family. In cases where sperm function cannot be restored, consider consulting with a fertility specialist to explore your options.

Other Potential Side Effects of TRT

It's important to discuss not only the benefits, but also the risks, of testosterone replacement therapy. In addition to positive effects like increased libido and muscle mass, TRT also carries various risks - aside from its impact on sperm production and fertility.

Potential side effects may include:

• Polycythemia (increased red blood cell count)
• Atrophy of the testes
• Elevated blood pressure
• Effects on heart and liver function
• Swelling in the legs or arms
• Mood swings or irritability
• Acne or oily skin

To minimize these risks, healthcare providers conduct regular blood tests to monitor testosterone levels, red blood cell counts, and liver function, screen for prostate cancer and assess cardiovascular health, and adjust your dosage as needed.

Alternative Treatments for Low Testosterone

If your healthcare provider finds that you have low testosterone levels, don't panic!

Remember that there are other treatments you can explore besides testosterone replacement therapy. Ask your doctor why your testosterone levels are decreasing and if you have any other medical conditions that may be causing that drop in testosterone.

Correcting a medical condition may increase your testosterone level without needing testosterone placement therapy. In addition, there are lifestyle changes which can naturally increase testosterone levels, including healthy eating, good sleep habits, and regular exercise.

Note: Your healthcare team may have you try lifestyle modifications prior to starting testosterone. Always talk to your doctor before trying new medications, supplements, or workout routines to ensure they are the right fit!

TRT and Sexual Function

The role of testosterone in sexual desire and function is significant, and many of the changes that occur as men age can be attributed to decreased testosterone production.

Some of my patients in their 40s report experiencing fewer spontaneous erections and lower sexual drive. In addition, they may notice a reduction in muscle mass and decreased energy to complete activities that were easier in the past.

Causes of Low Libido

Many men on testosterone replacement therapy have great success, reporting increased sexual desire and performance along with better mood and higher self-confidence. However, before starting TRT, your doctor should always make sure there are not other factors causing decreased libido.

If other causes are discovered, these may be corrected without using testosterone replacement therapy. A healthy diet and regular exercise can increase your body's production of testosterone in many cases.

Men's Health 101

Learn the lingo of male fertility, common health risks to be aware of, and how being proactive is key to a long, healthy life.

What You Should Know About TRT

Ultimately, a thorough discussion of the risks and benefits of testosterone replacement therapy (TRT) will be the key to your success.

While TRT can significantly improve quality of life for those experiencing low testosterone levels or undergoing a gender transition, it should always be carefully managed by healthcare professionals to ensure safety and effectiveness.

Discussing topics as personal as sexual function and reproduction can feel challenging, but it's important to be open and honest with your healthcare providers. Tell them what you're experiencing, what your goals are, and any concerns you may have.

With the right experts by your side, you'll be able to explore all of your options and find the best solution - without compromising your fertility.