What is the effect of Finasteride (generic name) on male fertility?

Effect of Finasteride on Male Fertility

Finasteride can negatively impact male fertility by decreasing ejaculate volume and potentially causing oligospermia, but these effects are typically reversible upon discontinuation of the medication. 1

Mechanism and Effects on Fertility

Finasteride works by inhibiting the 5-alpha-reductase enzyme, which converts testosterone to dihydrotestosterone (DHT). This mechanism affects male reproductive function in several ways:

• Semen parameters: FDA labeling indicates that finasteride treatment for 24 weeks in healthy volunteers resulted in:

  • 22.1% median decrease in ejaculate volume
  • Reduction in total sperm per ejaculate
  • These parameters remained within normal range 1

• Reversibility: The effects on semen parameters are typically reversible upon discontinuation, with an average time to return to baseline of 84 weeks 1

• Post-marketing reports: There have been reports of male infertility and poor seminal quality associated with finasteride use, with normalization or improvement after discontinuation 1

Clinical Evidence and Case Reports

Several case reports highlight the potential impact of finasteride on fertility:

• Cases of young men with severely reduced semen quality during finasteride treatment (1 mg/day) that improved after cessation 2

• A case of secondary infertility in a 40-year-old man after prolonged use of low-dose finasteride, with regression of impaired semen parameters and sperm DNA fragmentation after discontinuation, resulting in successful pregnancy 3

• A report of a couple achieving successful pregnancy and live birth after the male partner discontinued finasteride following 10 years of use 4

Risk Factors for Fertility Impact

The impact of finasteride on fertility may be amplified in men with:

1. Pre-existing fertility issues
2. Varicocele
3. Obesity 2

Recommendations for Men Planning Pregnancy

For men taking finasteride who are planning pregnancy:

1. Consider discontinuation: If actively trying to conceive, discuss discontinuing finasteride with a healthcare provider

2. Timing: Allow sufficient time (at least 3-6 months) after discontinuation before attempting conception to allow for semen parameter improvement

3. Monitoring: Consider semen analysis if conception is delayed

4. Specialist referral: Men with abnormal semen parameters should be evaluated by a male reproductive expert 5

Additional Considerations

• Dose effects: Both 1 mg (hair loss) and 5 mg (BPH) doses have similar effects on DHT levels, reducing it by approximately 50% 1

• Animal studies: In animal studies, finasteride has shown effects on accessory sex organs and fertility at high doses, but these findings may not be directly applicable to humans 1

• Long-term use: Even after long-term use (10+ years), fertility can recover after discontinuation 4

Conclusion

While finasteride can impact male fertility parameters, these effects appear to be reversible in most cases after discontinuation of the medication. Men taking finasteride who are planning to conceive should discuss the timing of medication discontinuation with their healthcare provider.