what do people think about this data
basically for this theory to work you have to assume that in the first study with 0.05mg the result is an outliner since it is very unlikely that the negative trend of lower dose lower scale dht does not continue at 0.05mg and the sample size is also high as well as the confidence interval being highest.
so lower dose leads to lower reduction of tissue dht which then leads to lower hair count as shown in the second study, 1mg is superior to 0.2mg on ALL end points(so much to the "lower dose just as effective") which is likely not true. if it was true why would Merck not have made 0.2mg pills? they could have set the price anyway, there was no law what a gram of finasteride should cost. clearly because in this dose ranging study they have found out that 1mg is the best dosage for hair growth
so if it is the best dose and scalp dht is higher in a lower dose, it means there is more local 5AR activity which in my opinion should also mean less side effects because this should hold true for other tissues as well. and because of that 5mg is used in prostate hyperplasia
they have also shown 0.1mg (where some men claim to have side effects on online forums) that serum and scalp dht were not suppressed significantly compared to placebo and that hair count (while better) this was not statistically significant.
so 0.1mg should not lead to systemic side effects even after many months because there is not enough accumulation to outcompete the half life and reproduction of 5AR. now, if you apply topical about 20% should reach the blood stream but the scalp is the first tissue affected so a lot of 5AR should be binding to finasteride immediately. the 20% enters the blood stream so if we apply 0.5mg about 0.1mg should enter the blood stream which has not been shown to markedly impact serum dht in the dose ranging(only 10%). but in the recent study a 35% reduction in serum dht could be seen
this could mean two things: first, topical penetrates more than by 20% but also obviously not all of it penetrates
or since topical finasteride whips out 60% of scalp dht less dht is released into blood hence why we can see a diminished level in serum.
but then there is other things that dont make sense. for example how can finastetie concentration be 1/150th of oral but have similar dht suppression abilities yet when you take 0.01mg oral which is also 1/100th of 1mg you have barely any systemic suppression?
I still think it is worth exploring, evidently there are not enough studies so people just need to try out for themselves, mozzarella showed promising results in a 0.005% trial even which should absolutely not affect serum dht and based on his studies claims it did not however I have not seen the full study as off yet. it was 16 month too so it actually says something instead of 5 month Kintor study which barely allows any conclusions.
