Will it make a difference if I change from propecia to generic finasteride?

By law a generic medication has to have at least 80% of the bioavailability of the active medication.  The vast majority of my patients have noticed no difference in effect and have been very happy with the savings.  A very few, however, have noted more hair loss after switching which improved after resuming the brand name.

Excellent and very frequent question. No, unfortunately my personal experience in USA, Spain and Mexico (for my patients) has not been the same results when we had to switch from the brand to generic. The brand is more expensive but I have seen more consistent results. The other option is to buy the Brand Proscar (5 mg Finasteride) cut the tablet in 4 pieces (1.25 mg each) and take 1 piece daily. Good luck. 

Most generics are pretty close in strength to their name brand drugs.  In the US it is the law; but sometimes they are a bit weaker.  See what happens when you switch. Make sure that the savings are significant enough before you try.

The FDA reviews all of the manufacturing of propecia such that a genetic is supposed to be the same and the original

By all means use the generic form. There is absolutely no difference between name brand and generic when it comes to Finasteride.