It helps but if propecia stopped male pattern baldness in majority of people then it seems to me most men would be able to prevent male pattern baldness and hair transplant guys would be out of jobs. So it seems propecia does not work perfectly and most hair transplant guys say that even with propecia you generally still slowly lose ground over the years and genetics wins out. I dont know if they are lying or not but that is what a lot of doctors say
These "transplant guys" encounter people, in whom the treatment doesn't work. This is why their perception of the drugs' efficiacy is perversely skewed. (Something similar like on this forum.)
Recently, I discussed it with a transplant surgeon, who said that according to his experience, the anti-hairloss treatments lose their efficiacy after 3-5 years. For Goodness sake, all 5-years' studies on finasteride demonstrate that 90% men keep their hair after 5 years! And in the Rossi et al.'s study from 2011, 86% men persisted in their improvements even after 10 years!
As a "proof", this surgeon sent me a fresh email from his patient, in whom the treatment by finasteride allegedly "stopped working". But what I saw was a case of a man, who was gradually losing hair on finasteride for 10 years, and one day he suddenly lost an unusually big amount of hair. In other words, the treatment has never really worked in him, and one day it stopped "working" completely.
I am really disgusted to read this crap over and over again - after 16 successful years on anti-hairloss treatments. There are people using these treatments successfuly for 15, 20 or even 25 years (Beach man from HairlossHelp). Baldness is not an inevitable state. It has no direct relationship with the aging process. It is a hormonally induced problem. If you eliminate this hormonal influence, it won't happen. How could you lose hair on finasteride or dutasteride, when your DHT is on the level of a 15-years' old kid? Almost everytime, when I see some unsuccessful case and hormonal data are available, it's crazily hyperandrogenic guys with total testosterone around 1000 ng/dl and DHT 100 ng/dl. Naturally, they can't succeed with finasteride, because it will only lower their DHT on the level of an average man, and if they use dutasteride, their testosterone will explode like in men on steroids.
And remember that the majority of men are simply ignorant. Recently, I went to my local doctor and asked her for a prescription for finasteride. She heard this word for the first time in her life!