I think that many men have a permanent reaction to propecia however its only a smaller subset of these men that experience this reaction in a particularly negative way. The reason I say this is because I realized the other day that stories like the following are pretty common on hairloss sites:
https://www.baldtruthtalk.com/threads/24262-24-year-old-Finasteride-stopped-working.
Ive seen countless stories of guys talking about how finasteride has stopped working for them after X months/years. Whats interesting about this is that its a very similar time frame for guys that got PFS too. Many (not all) PFS guys got PFS after taking finasteride for X months/years. So basically the takeaway from this is that it appears that for many men it takes many months or maybe even a year or more for the body to begin to permanently react towards a given stimulus. In the case of some men taking finasteride their body reacts by making finasteride no longer effective and their hairloss starts again, in the case of other men it makes their bodies react by getting PFS.
I think the important thing to consider here is that we actually have a vast amount of cases where the time for permanent reactions (epigenetic shifts?) to occur is anywhere from months to a year or more. This is significant because we now have a concrete idea of how long it takes to cause an epigenetic shift. This is knowledge that we were previously unaware of but it was right under our noses so to speak. Armed with this knowledge we can possibly learn to treat PFS better due to knowing that it may take many months or even a year or more to see results by using a particular approach. I think all too often people here are prone to giving up a certain approach after only a few weeks or even a few days. I know that im certainly guilty of this. I think that if we began to adopt a more diligent and medium/long term approach then its possible that we could see positive results from different treatments which we had previously considered deadends