Patty, I have no idea why Iodoral has proven more effective for many of us. It's supposed to be essentially the same chemical combination as Lugol's. Iodoral may be absorbed lower down in the digestive system and that may effect absorption or pathways.
I used Lugol's for months. Then I took 4 Iodoral one morning. I just "woke up." I got more energy and my mind got quicker that first day. Some others report the same thing. Some don't notice any difference mentally.