I know Iodorol & Lugol's is the most economical and that we need aprox. 200 to 400 mcg of selenium a day, and 500 mg of niacin is highly recommended, BUT.... (1) I don't tolerate niacin at the recommended doses for ATP CoFactors AND (2)I have six adult relatives I'm working with encouraging them to take iodine, and they may not tolerate niacin either. (3) I believe if I told them to take more than one tablet a day, I doubt they'd do it. They are all dealing with fatigue and "foggy brain" issues. Taking one pill a day is simpler and provides a greater chance for compliance. In fact, I've already heard back from my ADHD son. He's been taking I O Plus for several weeks now and he's already experiencing positive results! Later on, I may encourage him to double the dose, but for now, I'm thrilled he's taking one 12.5 mg tablet daily. Whoo hoo!