Hi Dr,
We know that the study on Propecia shows that after five years, users typically lose most of their regrown hair, and that propecia continues to deter hairloss but that hairloss does continue over time.
My question is…why? Is it that Propecia no longer effectively inhibits DHT after 5 years (body develops an immunity, DHT serum/scalp levels therefore increase.) Or, more likely, is it that there are still undetermined factors which contribute to hairloss, even though the type 2 DHT inhibition rate remains constant?
The question links to avodart. If avodart is just a *much* stronger DHT blocker, and if DHT-inhibition is not the cure-all to hairloss, can’t we expect that Avodart too is equally limited in its scope?
I don’t see how type 1 inhibition and long half life can help in the overall process if there’s more ground to cover than DHT inhibition.
Actually, Propecia users keep more hair than non-Propecia users even after 5 years (ie they do not lose most of their retained hair), and Propecia continues to stop or slow hair loss at the very least in the crown area for as long as you take it. I have patients who have been on it since it came out and their hair loss (if any) is undetectable.
As for those who only experience dramatically slowed loss (still a big improvement), no one knows why hair loss continues at low levels. You are correct to point out that we do not have all the answers with hair loss, the fact that Propecia works mainly in the crown for returning hair and not the front (and only in men) is proof of this. But Propecia will slow loss in the front if you catch it early enough in some people. Pattern baldness is progressive by its very nature.
You are also correct to point out that Avodart is far from being a panacea. We do not even have studies proving it’s efficacy in hair retention (although I myself believe it possible), so it cannot be the final answer or the magic pill we all hope for. Before starting more medications, you should get a metric (measurement) by having your scalp mapped out for miniaturization to determine if you have premature genetic balding.
There are still many unknown factors in hair loss, the future will bring many advances and surprises, I am sure. Until then, Propecia, Rogaine, and hair transplantation are the only means of hair loss help that have scientific evidence to prove and quantify their effectiveness.