I've been researching vanadyl sulfate. It does sound promising however, one sight mentions the possibility of a mild side effect of diarrhea and loss of apetite. The diarrhea part stopped me cold, unfortunately. The IBS-D, for a long time, had a negative effect on my life. I was afraid to eat a meal and then go out to do errands or if I ate a meal and had to go out, I would take Imodium AD. Now that I have medication (cholestyramine) that helps tremendously with the diarrhea problem, I feel like I've gotten my life back. I felt that I needed to point that out so you could understand why I shy away from anything that has diarrhea as a possible side effect. Nevertheless, I really do appreciate your advice. My husband takes chromium picolonate but we will both now look for chromium polynicotinate.