Does Finasteride stop working?

No. Finasteride will eventually stabilize at some positive balance with your rate of hair loss. The original studies showed that over a 5-year period, men on finasteride lost less hair and kept more hair.  I know from my practice that men on finasteride for 20 years who decided to stop the drug came crying to me to get back on it as they experienced “Catch-up hair loss”, going back in the direction of the genetic hair loss they might have had if they didn’t take it.