The safety of finasteride has been well demonstrated in clinical studies. Nonetheless, <2% of men experienced some form of sexual dysfunction in the clinical trials – A small number of men experience lower sexual desire and/or difficulty in achieving/maintaining an erection. An even smaller number may have a decrease in semen volume. The sexual side effects generally resolved in men who stopped taking finasteride and in many men who continued treatment. Another medication to consider is Minoxidil.
Propecia product information. U.S. Food & Drug Administration.
Health Science Authority, Singapore