Both finasteride and dutasteride are competitive 5AR enzymes inhibitors. That means they bind to the 5AR enzymes' active sites, so renders the 5AR enzymes useless. Unfortunately, competitive inhibitors are also reversible! Meaning that if there are enough substrates concentration (testosterones), it can displace the inhibitors!
So, if finasteride/dutasteride not workingfor you, maybe try upping the dosage?
Looks like finasteride and dutasteride are irreversible inhibitors, even though most competitive inhibitors are reversible inhibitors! This is awesome.
But dutasteride needs to have higher dosage to have a long terminal half-life, micro-dose like 0.1mg won't have long half time. And in most cases higher dosage is better to those who care about their hair.
finasteride (and I believe dutasteride, but not certain) are suicide inhibitors. They form a stable enzyme/substrate complex that is an irreversible bond, rendering both the original enzyme and substrate non-functional. Whilst it's true that some competitive inhibitors can only form reversible reactions, I believe due to the steroidal classification of finasteride and dutasteride, they have a high binding affinity to the AR and are thus not reversible. This is not something that you need to worry about.
