Androgen Levels and Semen Parameters in Men with Persistent Sexual Adverse Effects After Using a 5α-Reductase Inhibitor

Recent studies and warnings from the US Food and Drug Administration have highlighted the potential for persistent sexual and nonsexual adverse effects following the use of a 5α-reductase inhibitor for male pattern hair loss. This medication, designed to block the conversion of testosterone to dihydrotestosterone (DHT), has been associated with serious reproductive health issues, including male infertility. Alarmingly, some men have reported ongoing sexual dysfunction even after discontinuing the drug. This study by Dr. Michael S. Irwig aimed to explore whether these men exhibit lower androgen levels and impaired semen quality compared to typical reference populations.

The study involved 24 otherwise healthy young men who had used a 5α-reductase inhibitor (1.00-1.25 mg/d) for hair loss and developed persistent sexual side effects. The participants underwent interviews and provided multiple blood samples for hormone analysis and semen samples to assess fertility parameters.

The findings were concerning. Although average androgen levels (testosterone and DHT) were within normal ranges, 13% of the participants had confirmed low levels of both androgens—higher than the 5% expected in the general population. Furthermore, semen analysis revealed that 16% of the participants had severe oligospermia (sperm concentration below 5 million/mL), a condition affecting only about 3% of fertile men. Additionally, 44% of participants showed low sperm motility, and 50% had abnormal sperm morphology.

These results suggest that while serum androgen levels alone may not fully explain the persistent sexual dysfunction observed in these men, the impact on fertility is significant. The prevalence of low sperm counts, poor motility, and abnormal morphology points to a profound effect on reproductive health that could have lasting consequences.

It’s important to note the limitations of this study, including the absence of baseline androgen levels and semen parameters before the drug’s use, as well as the small sample size. However, the findings underscore the need for further research to understand why certain men are more susceptible to the long-term effects of 5α-reductase inhibitors. The potential for irreversible damage to reproductive health raises serious concerns for those considering or currently using this medication.

Read the full study here.