From what I understand, Type I seems to play a significant role in inflammation of the scalp. Excessive sebum production is a result of sensitivity to androgens in the scalp. For years I have had extreme itch, scalp bleeding, and some kind of sticky film that collected on my scalp, neck, ears, and face. It definately felt like some sort of allergic reaction, except it was constant.
High doses of saw palmetto (the kind with 95% fatty acids) relieved the itch for me. Finasteride also plays a role, but to what extent I am not sure. I took the palmetto before ever taking propecia, so I know it had its own independent effects I felt them about 1 month on palmetto only.
From my own experience, both of these drugs have played a role in bringing down my scalp itch by probably 90%. The problem is the side effects, and I would say finasteride is the worst of the two drugs. I had absolutely no sex drive while on the stuff, it also had interactions with anti-anxiety drugs because of the depletion of allopregnanalone due to the inhibition of of type II 5 alpha reductase. The severe sides I experienced on finasteride were simply terrible, and they weren't part of my imagination. I had no concentration, tremendous anxiety, panic, depression, and complete loss of libido and erections. Type II may not be found in brain tissue, but it certainly has some effect on the nervous system.
Now as to saw palmetto, this drug really seemed to bring my itch under control, and from what I have read, it only inhibits Type I, so its not like finasteride. Apparently, Type I is found in the brain tissue, hair follicles, and it effects sebum production. I definately experienced sides from Palmetto, but not to the extent of finasteride which is strange. My itch really went down on this stuff almost immediately, this could also be because of its alleged anti-inflammatory properties in general. Sexual sides were mild from palmetto, infact I think I may have had even increased libido, the drug is worlds apart from propecia in this way. But there are other risks, like gastric bleeding (at higher doses and in conjunction with NSAIDS). I also noticed some insomnia, and there were definate interactions with anti-anxiety meds that are dependant on the proper levels of neurosteroids.
I would imagine that dutasteride would be the ultimate treatment for scalp itch because it inhibits both types of 5AR but I would never dream of taking this stuff because of my bad reaction to finasteride. Plus the half life of dutasteride is 1-2 months, so if you are sensitive to these things like me, you could really be playing with fire, as far as long term consequences are concerned.
