Finasteride in Young Men: Effects on Semen and Hormones?

 Finasteride in Young Men: Effects on Semen and Hormones?

Mohamed Farouk Allam, MPH, PhD (1,2)

1. Department of Family Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt.

2. Department of Preventive Medicine and Public Health, Faculty of Medicine, University of Cordoba, Cordoba, Spain.

 

Qeios (2025): https://www.qeios.com/read/16UWBQ

 

DOI: 10.32388/16UWBQ

 

Abstract

Finasteride is widely used to treat male androgenetic alopecia (AGA) and has been shown to significantly improve hair count and appearance compared to placebo. Despite its effectiveness, concerns remain about its potential sexual adverse effects. While some studies suggest these effects are rare and reversible, the evidence is inconsistent. Notably, the dosage appears to influence reproductive outcomes: the common 1 mg dose shows minimal impact on sperm parameters, whereas the higher 5 mg dose is linked to reduced sperm count, motility, and volume, highlighting a dose dependent effect and individual variability. A widely cited 2014 study by Irwig suggesting long-term sexual side effects has major flaws, including selection bias, lack of a control group, small sample size, and inadequate statistical methods. Most participants were recruited from a forum for users with negative experiences, making the findings unrepresentative. In contrast, a 2013 prospective study by Samplaski and collaborators found that most men saw improved sperm counts after stopping finasteride, with hormone levels and sperm quality remaining stable. Overall, while finasteride may affect fertility in some men, robust conclusions about long-term sexual side effects require larger, better-designed prospective studies to ensure accuracy and generalizability.

 

Keywords: Finasteride; semen parameters; androgen levels; 5-α-reductase inhibitors; sexual functions; review.

 

Mohamed Farouk Allam. (2025). Finasteride in Young Men: Effects on Semen and Hormones?. Qeios. doi:10.32388/16UWBQ.

 

https://www.qeios.com/read/16UWBQ