Propecia Effectiveness Studies?

hi dr rassman, are there any studies to show the ratio of propecia users who have used for several yrs and then the drug loses its effectiveness, for instance 80% or 8 out of 10

There are no studies I am aware of that show such information. There are some general observations that I have made about finasteride which are strictly my opinion, however. Finasteride works better:

1. in younger men or when the hair loss is more recent (less than 2 -3 years)
2. in the crown for restoring hair
3. to prevent rather than restore hair in the front
4. to prevent shock hair loss after a transplant if it is started prior to the transplant
5. when the initial results are impressive, rather than at the end of the 5th year when the progressive nature of the hair loss continues with its slow progression