The Iodine is definitely causing a reaction that is leading to the constipation. When I stop using it i have 3 bowel movements a day. When i'm on it I don't go at all.
That said, I have been diligent about taking the co-factors including 4 capsules of 500mg Ester C as well as plenty of Selenium and they just don't see to make a dent in the rate of digestions / constipation.