yes I am referring to DHT circulation in the blood
Difference between Serum and Plasma. Serum is the fluid from blood without the clotting factors while Plasma is the fluid that contain clotting factors.
microbiologyinfo.com
note that just like testosterone, dht is bound to SHBG even more so than T so free DHT is what your body would actually have available. also not that serum dht is not the entire picture, I think the best predictor would be tissue dht and for side effects, the best predictor to not get any sides is if you have low impact on localized dht in organs like the penis and the brain. you can have marked serum dht reduction but a less evident decrease in certain target organs. you want to maximize the DHT reduction in the scalp and minimize it in the penis and the brain.
sure, very small doses like 0.2mg of finasteride can cause 60% reduction of plasma, just about 5-10% less than 1mg. but what about those tissue dht? evidently 0.25mg causes less hair count recovery as 5mg, markedly less so which means there is higher localized androgenic activity in the scalp with lower dose despite comparable serum impact. if this is true for scalp it can be true for the penis and the nervous system as well. basically when people say it goes systemic they dont know what they are talking about.
however sides I think cannot be totally avoided but the study I posted I think had a higher drop out rate due to sides in the placebo group and despite high dropout rate in all groups this was quite evident.
i am going to try the glass droppers as well. it is very hard to use spray when you need to cover a NW5 area if you only want to use 1-2ml