Does finasteride (a 5-alpha-reductase inhibitor) have any effect on male fertility after stopping the medication?

Finasteride's Effect on Male Fertility After Discontinuation

Finasteride can temporarily affect male fertility parameters, but these effects are generally reversible after discontinuation of the medication.

Effects on Fertility Parameters During Treatment

Finasteride, a 5α-reductase inhibitor (5-ARI), has several documented effects on male reproductive parameters while taking the medication:

• Semen parameters:

  • Reduces ejaculate volume by approximately 0.6 mL (22.1%) 1
  • Can decrease total sperm count (11.6-fold increase observed after discontinuation in men with subfertility) 2
  • May cause mild decreases in sperm motility (6-12% reduction) 3
  • Can affect sperm morphology with increased abnormal forms 4

• Hormonal effects:

  • Reduces dihydrotestosterone (DHT) levels by approximately 70% 5
  • May transiently increase testosterone levels 3, 4

Reversibility After Discontinuation

The FDA label indicates that the changes in semen parameters "remained within the normal range and were reversible upon discontinuation of therapy with an average time to return to baseline of 84 weeks" 1.

Research studies support this reversibility:

• In men with oligospermia, sperm concentration increased after finasteride discontinuation 6, 2
• 57% of men with severe oligospermia (<5 million/mL) had counts increase to >15 million/mL after cessation 2
• No man had a decrease in sperm count after discontinuation 2
• Most semen parameters return to near-baseline levels within 24 weeks after stopping treatment 3

Clinical Implications for Fertility

For men planning pregnancy:

• Consider discontinuation: If a man is taking finasteride and planning pregnancy, discontinuation should be considered, particularly in those with pre-existing subfertility 6, 2

• Recovery timeline: Improvement in semen parameters may be observed within 1-4 months after discontinuation 6, 2, though complete recovery may take longer (up to 84 weeks according to FDA labeling) 1

• Case evidence: There is documented evidence of successful pregnancy after long-term finasteride use following discontinuation 7

Special Considerations

1. Pre-existing fertility issues: Men with pre-existing impaired spermatogenesis may be more vulnerable to finasteride's effects on fertility 6

2. Duration of treatment: The FDA label notes postmarketing reports of "male infertility and/or poor seminal quality" with finasteride use, with "normalization or improvement of poor seminal quality after discontinuation" 1

3. Dose considerations: Even low doses (1mg) used for androgenic alopecia can affect fertility parameters 6, 2, 4

Recommendations

For men concerned about fertility:

1. Discontinue finasteride when actively trying to conceive, especially if there are pre-existing fertility concerns

2. Allow sufficient time (at least 3-6 months) after discontinuation before attempting conception to allow for recovery of semen parameters

3. Consider semen analysis before and after discontinuation in men with known or suspected fertility issues

4. Consult with a fertility specialist if pregnancy is not achieved within a reasonable timeframe after discontinuation

While finasteride can temporarily affect male fertility parameters, the evidence suggests these effects are generally reversible after discontinuation of the medication, with successful pregnancies possible even after long-term use.