Testicular shrinkage, or testicular atrophy, can occur during testosterone replacement therapy (TRT), usually because treatment suppresses the body’s natural testosterone production and reduces stimulation of the testicles.
This is not always harmful, but its significance depends on fertility goals, symptoms, and individual concerns about physical changes.
This guide explains why testicular atrophy can occur during TRT, whether it is clinically significant, and what options may help protect fertility or reduce the risk of shrinkage.
- Why do testicles shrink on TRT?
- How much can testicles shrink on TRT?
- Is testicle shrinkage on TRT harmful?
- Is testicle shrinkage reversible?
- Fertility, testicle shrinkage, and TRT
- How Leger can help
Why do testicles shrink on TRT?
The testicles rely on hormonal signals from the brain to produce testosterone and sperm. When TRT is started, circulating testosterone levels rise, which can suppress luteinising hormone (LH) and follicle-stimulating hormone (FSH). As these signals fall, the testicles become less active and can reduce in size.
How much can testicles shrink on TRT?
Some degree of testicular shrinkage is common during TRT, and, although the extent varies, most men will notice a visible reduction in size.
A practical estimate is a reduction of around 3 ml in testicular volume, although measurement methods vary between studies [1].
When testicular shrinkage occurs, it usually develops gradually during the first few months of treatment and typically stabilises, rather than continuing indefinitely.
Is testicle shrinkage on TRT harmful?
Usually, the shrinkage itself isn’t harmful, and it’s more of a cosmetic or psychological issue than a medical problem. Whether it matters to you depends on what else is going on.
It can matter more if:
- You want to preserve fertility
- You notice a drop in ejaculate volume
- You feel discomfort or a sense of heaviness
- The change bothers you personally or affects your confidence
Is testicle shrinkage reversible?
TRT-related testicular shrinkage can improve if treatment is stopped, although recovery is not guaranteed, and the timeline can vary. In some men, hCG may also help maintain or restore testicular stimulation by mimicking LH, which can support testicular volume and fertility.
Recovery of fertility may take longer than recovery of testicular size, and both should be managed with appropriate clinical guidance.
Recovery can depend on:
- How long you have been on TRT
- Your baseline hormone function before treatment
- Whether fertility-preserving treatment is used
- Your general health and age
Fertility, testicle shrinkage, and TRT
Fertility is one of the biggest reasons why testicle shrinkage on TRT matters. If the testes are getting less LH and FSH stimulation, sperm production can fall, sometimes significantly. As the signals between your brain and testes decline, the testicles become less active, which is why they may shrink over time and why sperm production can drop as well.
How Leger can help
If fertility is important to you, it’s essential to discuss this before starting TRT. Our TRT specialists will take the time to understand your symptoms, health, and future fertility plans, so they can advise on the most appropriate next steps.
Where suitable, they can talk you through options that can help protect fertility while treating low testosterone symptoms or discuss alternative approaches if TRT is not the right choice for you.
Read our article on TRT and fertility to learn more.
Not sure where to start? Use our simple Get Started tool.
References
- Bhasin, S., Brito, J.P., Cunningham, G.R., Hayes, F.J., Hodis, H.N., Matsumoto, A.M., Snyder, P.J., Swerdloff, R.S. and Wu, F.C.W. (2018) ‘Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline’, The Journal of Clinical Endocrinology & Metabolism, 103(5), pp. 1715–1744.
Share:
Can low testosterone cause weight gain?