High doses may cause free oxygen radical-mediated toxicity of unabsorbed iron to the intestinal mucosa, worsening gastrointestinal symptoms and decreasing adherence to treatment.[17] In addition, hepcidin is the most important molecule regulating iron metabolism in mammals, and a slight increase in serum iron activates hepcidin to limit iron absorption.[9,18] A recent study examined daily, once-daily split and alternate day oral iron dosing regimens in women with moderate anemia. The gene discussed is HAMP; the disease is anemia.