GSTM1 and anemia (phenotype): However, being inexpensive and readily available, oral iron is still a viable option to start replacement in patients with mild anemia (Hb, 11.0–12.9 g/dl in men and 11.0–11.9 g/dl in non-pregnant women), but it should be continued only if the response to therapy is optimal (Hb increase by 2 g/dl within 4–8 weeks) and well tolerated1.