What causes decreased testicular size in patients undergoing Testosterone Replacement Therapy (TRT)?

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Last updated: April 12, 2025View editorial policy

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From the Guidelines

Testicular shrinkage is a common side effect of testosterone replacement therapy (TRT), and to mitigate this, human chorionic gonadotropin (hCG) can be added to the TRT regimen, as recommended in the 2024 AUA/ASRM guideline 1. This occurs because exogenous testosterone suppresses the body's natural production of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which normally stimulate the testes to produce testosterone and sperm. Key points to consider include:

  • The degree of response to hCG treatment correlates with the size of the testis prior to treatment 1.
  • Initial treatment with hCG injections (500-2500 IU, 2-3 times weekly) can help restore testosterone production and spermatogenesis, followed by FSH injections when indicated 1.
  • For men interested in current or future fertility, exogenous testosterone therapy should be avoided due to its inhibitory effects on spermatogenesis, and alternative treatments like hCG or selective estrogen receptor modulators (SERMs) may be considered 1. Some important considerations for patients on TRT include:
  • Regular monitoring with a healthcare provider to adjust the treatment plan based on individual needs and response to therapy.
  • The potential need to freeze sperm before starting TRT or temporarily stopping TRT to restore fertility.
  • The use of medications like clomiphene citrate or hCG to restore fertility, under the guidance of a healthcare provider 1.

From the Research

Decreased Testicular Size on TRT

  • Decreased testicular size is a potential effect of Testosterone Replacement Therapy (TRT) 2
  • TRT can cause progressive testicular atrophy, as observed in a study comparing human chorionic gonadotropin (hCG) therapy and TRT in men with male hypogonadotropic hypogonadism (MHH) 2
  • The use of hCG therapy may be a viable alternative to TRT, as it can improve testosterone production and sperm production without the negative effects on fertility seen with TRT 3, 4
  • Concomitant intramuscular hCG may preserve spermatogenesis in men undergoing TRT, potentially reducing the risk of decreased testicular size 3
  • The effects of TRT on testicular size and fertility are important considerations for men undergoing treatment, and alternative therapies such as hCG may be worth exploring 5, 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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