Type I and Type II DHT

I don’t understand the difference between Type I and Type II DHT. Why does finasteride only block Type II? DHT is DHT right? Also, if you’re going to lower DHT levels by blocking it from forming, why not just block all of it?

In the clinical trials for Propecia, I heard they tested finasteride at 20mg and its effects on hair loss were marginally better or more or less the same. And if Propecia is great but not perfect, there must be something else causing hair loss, perhaps another enzyme acing on type II or 5AR or another enzyme acting on Type I DHT.

Is it possible for Propecia to cease hair loss where it is forever?

Cheers for your time.

DHT is DHT. It works on different receptors in the body and these are discussed on RXList.com. Essentially, “The type 2 isoenzyme is primarily active in the reproductive tissues, while the type 1 isoenzyme is also responsible for testosterone conversion in the skin and liver.”

The last question in your message is not clear. If you are asking if taking Propecia forever will keep the DHT blocked at the same level forever, then the answer is no. There is no forever anti-DHT treatment. Your body will eventually start to produce more DHT than Propecia will be capable of combating, and you may begin to see hair loss again years and years down the line. Some doctors actually increase the dose of Propecia to combat at progressive ineffectiveness, but there is no proof that a higher dose works, but it may be a logical direction to go if the drug is less effective after years.