el_duterino said:
Bryan, thanks. So you are saying that:
What we measure as "scalp DHT" is only the DHT created in the scalp, and that DHT created in other body organs does not make it to the scalp, and does not increase it.
Well, not
significantly, anyway. I wouldn't lose any sleep over the relatively small amount that may get there from other tissues.
BTW, I've never been particularly interested in so-called "scalp DHT", for the simple reason that there's more than just one source of DHT, even in the scalp!
For example, sebaceous glands are certainly a rich source of the 5a-reductase type 1 enzyme, and they produce lots of DHT. In fact, I've read that _most_ of the DHT in a scalp biopsy actually comes from the type 1 enzyme (probably from sebaceous glands). I've always been puzzled about why there's so much interest in so-called "scalp DHT" on hairloss sites. That concept doesn't really narrow it down very much to the hair follicles!
What should really be the object of interest on hairloss sites, in my opinion, should be
follicular DHT, not "scalp DHT".
el_duterino said:
If that is correct, the second question is how can we effectively inhibit 100 % of the scalp DHT conversion.
WOW. You want to suppress 100% of DHT in the scalp?? You really aim HIGH, don't you?
el_duterino said:
I mean, do we need a CONTINUOUS application of a finasteride/dutasteride topical ? I suppose that applying a finasteride/dutasteride topical once a day would not be sufficient since it will work for a few hours only (or even less ?) .
Well, this is all getting complicated. You're forgetting that both finasteride and dutasteride are considered to be
irreversible inhibitors of 5a-reductase, so you're not necessarily going to need a continuous exposure to those inhibitors to get a very significant suppression of DHT. In fact, blood levels of finstaride drop by about an order of magnitude over the course of a day, when you're taking a single dose once a day.
But yeah, if you're going to try to get MASSIVE suppression of DHT like close to 100%, you're probably going to have to have some serious around-the-clock exposure to the drugs. Certainly with finasteride.
el_duterino said:
At least taking finasteride/dutasteride internally does inhibit a good amount of scalp DHT in a continuous fashion over the day since the drug stays in the blood in sufficient amounts all the time.
Any thoughts ?
Again, the level of finasteride in the blood drops by about an order of magnitude over the course of the day, when you take a single dose per day. Check out this graph:
http://img218.imageshack.us/img218/7561/fin5bfx1.jpg
(blood concentrations of finasteride during 24 hours)
You need to keep in mind that the scale in that graph is
logarithmic, so the blood level of finastide is dropping even faster than what it may appear to be doing in that graph at first glance.