How common is Post Finasteride Syndrome from the perspective of a doctor?

Hello,
In most of the male cases Finasteride would work. If it doesn't work than there might be a hormonal disfunction or, the person may be in lack of blood. But usually finasteride works.

Out of tens of thousands of Propecia users in our practice over more than the last decade I am aware of only a handful of patients that might fall into the category of Post Finasteride Syndrome. In our experience it has been extremely rare.

In my clinic, where I or Dr. B.L. Limmer have treated over 10,000 patients with Propecia/Finasteride,  can recall only one case of a patient who was convinced he had PFS. This patient also suffered from anxiety, depression and other illness. The syndrome, if it fact it even exists, is very rare. Sexual function is a multifactorial issue; it is both physical and psychological. So, patients with psychiatric and/or other medical illness are predisposed to having erectile dysfunction regardless of Finasteride use. Furthermore, 50% of all men over the age of 50 have some element of erectile dysfunction so it is an unfortunate but common problem that many men face as they age.