Recent reports have linked finasteride - marketed as Propecia - with persistent and possibly irreversible sexual dysfunction. Propecia, which treats hair loss, works by decreasing the conversion of testosterone to dihydrotestosterone, a hormone that causes hair loss.
In fact, doctors have known for years that Propecia has been linked to sexual problems including impotence, but a recent Propecia study performed by George Washington University found that as much as 38% of all users have adverse sexual events based on dosage and duration.
These side effects include low sexual desire, problems with orgasms and erectile dysfunction. In addition to the sexual side effects, additional life threatening ailments may arise including an increased risk of developing an aggressive form of prostate cancer and breast cancer.
The study also determined that sexual dysfunction associated with taking the drug is persistent, and not reversible as was previously thought. The Propecia study found that the side effects from taking the drug lasted an average of 40 months, with 20% of the men having side effects lasting more than six years.