SGL
Hey, SGL,
I'm not sure what the mg/kg conversion for humans and other animals is, so I can't say whether or not the amounts in the studies I cited would be considered hugely excessive, comparatively speaking, in humans.
However, I think one can approach the question of dose this way: Above 5mg/day in humans, finasteride seems to have little additional effect. I have read in several places that there may be no point in giving people a dose above 5mg/day of finasteride, because the decrease in DHT levels above 5mg/day are not much different (I saw an abstract where they were treating men with 100mg/day!...in this case there was about an 80% reduction in DHT, vs. 70% at 10mg/day...it's here:
http://www.ncbi.nlm.nih.gov/entrez/quer ... t=Abstract). In fact, there is really only a very small difference in effect between 1 and 5mg finasteride.
Also, finasteride is highly specific. No study has been able to demonstrate its action at any site but 5-alpha reductase. It does not bind to any homone receptor, or any other hormone-metabolizing enyzme that anyone is aware of.
Finasteride, at extremely high doses, does start to inhibit type I 5-alpha-reductase. In other words, at massive doses, finasteride, at worst, starts to behave a little like dutasteride.
So, I think it's unlikely one can blame the effects of finasteride in these animal studies on excessive dose. As has been clearly demonstrated in humans, adding more finasteride than is needed to completely inhibit type-II 5-alpha reductase does little more than the normal therapeutic dose.
If combined inhibition of both types of 5-apha reductase were somehow to blame, at any rate, then I'd stay the hell away from dutasteride. IMHO, I am doubtful of such an explanation.