What is the relationship between cannabis use and erectile dysfunction, testosterone levels, and testicular size?

Cannabis Use and Its Effects on Male Sexual and Reproductive Health

Regular cannabis use is associated with increased risk of erectile dysfunction, testosterone deficiency, and potential testicular changes, with these effects being more pronounced in heavy users and those with cannabis abuse/dependence. 1

Effects on Erectile Function

Cannabis use has a complex relationship with erectile function that appears to be dose and frequency dependent:

• Cannabis abuse/dependence significantly increases risk of erectile dysfunction (ED) with a relative risk of 3.99 at 3 months to 1 year after diagnosis 1
• Heavy cannabis users (those using 6+ times/week) have higher rates of ED requiring phosphodiesterase-5 inhibitor (PDE5i) prescriptions 1
• The mechanism may involve:
  • Disruption of hypothalamic function affecting hormonal regulation
  • Direct effects on vascular function
  • Psychological factors including altered arousal patterns

Impact on Testosterone Levels

Cannabis use affects testosterone through multiple pathways:

• Cannabis abuse/dependence is associated with a 2.19 times higher risk of testosterone deficiency (defined as levels <300 ng/dL) 1
• THC (tetrahydrocannabinol), the main psychoactive component in cannabis, appears to:
  • Block gonadotropin-releasing hormone (GnRH) release from the hypothalamus
  • Lower luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels
  • Reduce testosterone production by Leydig cells in the testes 2

According to the American Urological Association guidelines, men with ED should have morning serum total testosterone levels measured, as hypogonadism is present in approximately 36% of men with sexual dysfunction 3.

Effects on Testicular Size and Function

Cannabis use may affect testicular structure and function:

• Chronic exposure has been associated with:
  • Testicular atrophy in animal studies 2
  • Altered spermatogenesis and reduced sperm quality 2
  • Changes in accessory reproductive organ weights 2
• The endocannabinoid system is present in male reproductive tissues, suggesting a direct pathway for cannabis to affect testicular function 4

Clinical Implications and Management

For men presenting with ED who use cannabis:

1. Assess cannabis use patterns - frequency, amount, and duration of use

2. Measure morning total testosterone levels as recommended by the AUA 3

   • Target range for normal testosterone: 300-950 ng/dL 5
   • Consider free testosterone measurement in borderline cases

3. Evaluate for other contributing factors to ED and low testosterone:

   • Cardiovascular disease risk factors (ED is a risk marker for CVD) 3
   • Other substance use
   • Psychological factors
   • Medications

4. Consider cannabis cessation or reduction if clinically significant ED or testosterone deficiency is present

5. For patients with testosterone deficiency:

   • Consider testosterone replacement therapy if indicated
   • Target testosterone levels in the mid-normal range (450-600 ng/dL) 5
   • Monitor hematocrit, PSA, and other parameters during treatment 5

Important Caveats and Considerations

• Reversibility: Many endocrine effects of cannabis appear reversible with cessation of use 2

• Individual variation: Not all cannabis users experience these effects, and there may be genetic or environmental factors that influence susceptibility

• Dose-dependence: Heavier use is generally associated with more pronounced effects 1

• Confounding factors: Cannabis users may have other lifestyle factors or health conditions that contribute to sexual dysfunction

• Research limitations: Much of the evidence comes from animal studies or observational human studies with potential selection bias 6

• Potential cancer risk: There is a possible link between cannabis use and testicular cancer, though evidence is limited 3

For men concerned about sexual health who use cannabis regularly, discussing the potential relationship between cannabis use and sexual/reproductive health is warranted, particularly for those with existing ED or testosterone deficiency.