Karen, I recall asking Laura if Algin had any iodine in it. If I recall correctly, Laura had said that NSP stated that there was no iodine. However, Algin, being a seaweed (am I right here?) probably does contain some iodine, at least to start with - I don't know if NSP removes it or what. Anyway, some people, particularly people with thyroid problems, are particularly sensitive to Iodine (I know I am) and iodine will do one of two things: Suppress the thyroid and make you hypothyroid (slow, constipated, brain fog, tired etc) or, will rev. your thyroid up (diarrhea, wired and overly energetic, fleeting thoughts, shakiness, and speeding heart rate, etc, etc.....) . If you already are getting enough iodine in your diet or multivitamin, just a little more left in the Algin tabs could push you over the edge. This can be dangerous, re: the rapid heartbeat. Rapid heartbeat also happens with me when I am magnesium deficient. <img src="/ubbthreads/images/graemlins/frown.gif" alt="" />