I got carbonyl iron supplement , since it's advertised that carbonyl is best absorb-able form of iron and it causes least side effects. Problem is that, I still do get some side effects which is slight upset of stomach and gastrointestinal tract, which is probably due to my higher sensitivity (I have IBS). It causes me slight discomfort, and I found that disturbing on long run. Should I take a look at heme iron polypeptide, polysaccharides, or others?