What should I do if my testicle changes shape after starting testosterone replacement therapy (TRT)?

Testicular Shape Change with Testosterone Replacement Therapy

Testicular size and shape changes are an expected, normal consequence of testosterone replacement therapy due to suppression of gonadotropin production, and this does not require treatment discontinuation unless you have concerns about fertility or notice other worrisome features like a discrete mass. 1

Understanding the Mechanism

• Testosterone replacement therapy causes down-regulation of gonadotropins (LH and FSH), which directly leads to diminished testicular size and altered consistency 1
• This testicular atrophy occurs because the testes no longer receive hormonal signals to produce testosterone or sperm when exogenous testosterone is administered 1
• Studies demonstrate testicular volume decreases by approximately 16-23% after 4-6 months of testosterone therapy, with the degree of shrinkage correlating directly with sperm count suppression 2

When This is Normal vs. Concerning

Normal expected changes:

• Bilateral, symmetric reduction in testicular size 1
• Softer consistency of both testicles 1
• Gradual onset over weeks to months 2

Concerning features requiring urgent evaluation:

• Unilateral change (only one testicle affected) 1
• Discrete hard mass or nodule within the testicle 1
• Rapid onset change over days rather than weeks 1
• Associated pain, tenderness, or swelling beyond the expected mild changes 1

Immediate Action Steps

If you notice concerning features (unilateral, discrete mass, rapid onset):

• Obtain testicular ultrasound immediately to rule out testicular cancer, as men with infertility or hypogonadism have increased risk 1
• Perform physical examination focusing on identifying any discrete masses versus diffuse atrophy 1

If changes are bilateral and symmetric (expected atrophy):

• No intervention is required; this is a normal physiological response 1
• Document baseline testicular size at your next monitoring visit 1
• Counsel that fertility will be greatly compromised during testosterone therapy 1, 3

Monitoring Protocol

• First follow-up visit should occur at 1-2 months after initiating testosterone to assess early side effects and efficacy 1, 3
• Subsequent monitoring visits every 3-6 months for the first year, then yearly 1, 3
• At each visit, assess symptomatic response, voiding symptoms, and perform digital rectal examination 1
• Measure serum testosterone, PSA, and hematocrit/hemoglobin at each monitoring visit 1, 3

Fertility Considerations

• If future fertility is desired, testosterone replacement therapy should be reconsidered, as it will greatly compromise spermatogenesis 1, 3
• Testicular size typically returns to normal 4-12 weeks after discontinuing testosterone therapy 2
• Spermatogenesis recovery can take 1-4 years after stopping treatment 1

Common Pitfall to Avoid

The critical error is assuming all testicular changes on testosterone are benign atrophy without performing proper examination. Men with hypogonadism, infertility, or testicular atrophy have an 18-fold higher odds of testicular cancer, and the presence of testicular microcalcification increases concurrent testicular cancer risk 8.5-fold 1. Any unilateral or asymmetric change warrants ultrasound evaluation to exclude malignancy.