I think Mazzarella study used too much.
If i remember correctly, they used 0,005% solution. That means they used 3mg per 60ml. 1ml equals 0.05mg.
They used 2ml in morning and 2ml at night. So 4ml per day. So they put 0.2mg of finasteride on their heads daily.
Lets say systemic absorption about 10% if used simply in ethanol and nothing else.
So it means they have 0.02mg of fina in their blood every day. We already know 0.05mg of oral fina is almost as effective in reducing dht than 1mg of oral fina. So I am not surprised 0.02mg of finasteride can cause sides.
Now, if we reduce the dosage by 3, so a solution of around 0.0016%, i think it can avoid sides completely. But i dont know if it will be effective..
0.0016% means 1mg per 60ml. It means you have 0.016mg of fina per ml. Lets say we use 2ml per day instead of 4ml, we are putting 0.032mg of fina on your head. With a systemic absorption of 10%, it means you have 0.0032mg of finasteride in your body.
0.0032mg vs 0.02mg !!!
It's around 6 time less!