Vanadyl sulfate is a dietary supplement that delivers the trace mineral vanadium. It is used by some people who want to support healthy blood sugar metabolism, though the evidence for this is still thin.
Standard doses supply just micrograms of elemental vanadium. At higher intakes, vanadium can become toxic and may harm the kidneys, liver, or blood cells. Anyone using blood-sugar-lowering drugs or anyone with kidney trouble should be especially careful.
This supplement cannot replace diabetes treatment.