Though there is a strong debate on whether DHT blockers really cause ED, there are case reports of finasteride causing decreased sperm count following its use which is a more serious side effect.
Propecia-induced spermatogenic failure: A report of two cases.
Fertil Steril. 2007 Dec 3
To describe the results of two cases of azoospermia and severe oligospermia in men during and after cessation of finasteride 1 mg.
DESIGN: Case report.
Tertiary-care hospital-based clinic for andrology/male infertility.
PATIENT(S): Two patients with azoospermia and severe oligospermia using finasteride 1 mg for hair loss.
INTERVENTION(S): Discontinuation of finasteride.
MAIN OUTCOME MEASURE(S): Improvement in sperm concentration.
RESULT(S): Patient A had documented azoospermia over 1 year and was initially booked for a testicular biopsy. Six months after discontinuation of finasteride 1 mg daily he showed improvement in sperm concentration to 5.5 x 10(6)/mL. Patient B had severe oligospermia with a sperm concentration of 4 x 10(6)/mL. Sperm concentration improved to 6.6 then 18.7 x 10(6)/mL at 3 and 6 months after stopping finasteride.
CONCLUSION(S): We report two cases of infertile patients with azoospermia or severe oligospermia who showed significant improvements in sperm concentrations 6 months after the discontinuation of finasteride. In one case, improvement in semen parameters prevented the need for testicular biopsy and corrected the azoospermia. Stopping finasteride in the infertility population may improve semen parameters, and may allow for less invasive fertility treatments.