Vit C doesn't cancel the Iodine process, but changes it. Lugol's contains both elemental Iodine and iodide. If you take it at the same time as Vit C, you'll get mostly, if not all, iodide. That still counts in the Iodine process and is frequently a little easier to handle than elemental iodine. If you want the elemental portion, take it away from Vit C or orange juice.