One of the most common and expected effects of male fertility treatment is an increase in testicular size or volume. This is a normal response and a positive sign that your body is producing more sperm.
Why It Happens
Male fertility treatment often involves medications that mimic the body’s natural hormones (LH and FSH). These hormones:
Stimulate the Leydig cells in the testes to produce testosterone
Activate the Sertoli cells to support sperm production
Together, this results in increased activity within the testes—which can lead to a noticeable increase in testicular size.
What to Expect
Mild to moderate increase in testicle size is common and typically not uncomfortable.
It often begins within a few weeks to months of treatment.
Some men may also notice increased firmness or fullness.
This change reflects higher sperm production and hormonal activity—which is the goal of treatment.
When to Be Concerned
You should only contact your doctor if you notice:
Pain or tenderness that persists
Significant asymmetry (one testicle grows much larger than the other)
Swelling that appears suddenly
Lumps, hardness, or abnormal texture
These are not typical responses and should be evaluated by a doctor.
A mild increase in testicular volume is a normal and expected effect of male fertility treatment. It’s a good indicator that your body is responding to therapy.
If any discomfort or unusual changes occur, contact your prescribing doctor through the portal.