Why do my testicles (testes) appear smaller before ejaculation compared to before arousal?

Testicular Volume Changes During Sexual Arousal and Pre-Ejaculation

Direct Answer

Your observation of smaller-appearing testicles before ejaculation compared to before arousal is a normal physiological phenomenon related to testicular elevation and contraction of the cremasteric muscle during sexual arousal, not an actual change in testicular volume. This is a positional and muscular change, not a true reduction in testicular size.

Understanding the Physiology

What Actually Happens During Arousal

• The cremasteric reflex causes testicular elevation during sexual arousal, pulling the testicles closer to the body as part of the normal sexual response 1
• This elevation makes the testicles appear smaller and more compact, even though the actual testicular volume remains unchanged 1
• The scrotum also contracts during arousal, which further contributes to the appearance of reduced size 1

Why This Occurs

• Testicular elevation is a protective mechanism and part of the ejaculatory reflex, preparing the reproductive system for ejaculation 1
• The cremasteric muscle contracts involuntarily during sexual stimulation, bringing the testicles upward and forward 1
• This is completely normal and does not indicate any pathology or actual volume loss 1

Important Distinctions

Actual Testicular Volume vs. Appearance

• True testicular volume (measured by ultrasound or orchidometer) does not change during the sexual response cycle 2, 3
• Normal testicular volume is considered to be >12 mL per testis, with volumes of 15-18 mL being typical for adult males 4, 3
• The appearance of size change is purely positional and muscular, not volumetric 1

When to Be Concerned About Testicular Size

You should only be concerned about testicular size if:

• Baseline testicular volume is consistently <12 mL when measured at rest, which is associated with impaired spermatogenesis 4, 3
• There is a size discrepancy between testicles >2 mL or 20%, which warrants ultrasound evaluation 3
• You have a history of cryptorchidism (undescended testicles), which can result in permanently smaller testicular volume 2, 4
• You experience actual testicular atrophy over time, which would be noticeable when not aroused 4, 3

Clinical Pearls

Normal Sexual Response

• The duration of preejaculatory sexual arousal can affect semen parameters (sperm concentration increases with longer arousal time), but does not affect testicular volume 5
• Testicular position returns to baseline after ejaculation and detumescence 1

Common Pitfalls to Avoid

• Do not confuse positional/muscular changes with actual testicular atrophy 4, 3
• Self-examination should be performed when relaxed and warm (such as after a shower), not during or after sexual arousal, to get accurate assessment of baseline testicular size 3
• If you have concerns about fertility or testicular function, proper evaluation includes measurement at rest, not during sexual activity 2, 4

Bottom Line

The apparent reduction in testicular size you observe before ejaculation is a normal consequence of cremasteric muscle contraction and testicular elevation during sexual arousal. This is not a pathological finding and does not indicate any dysfunction. Your testicles are not actually shrinking; they are simply being pulled closer to your body as part of the normal sexual response cycle 1.