FGF23 and Hypercalcemia: Ironically, FGF23 is also an effective calcium‐lowering hormone by virtue of its ability to suppress the principal calcemic hormone, 1,25(OH)2D. Finally, as expected in an endocrine sense, calcium is also a modulator of FGF23, with induction of FGF23 by hypercalcemia (Fig. 5B).