In recent randomized controlled trials of up to 5 weeks duration, intravenous iron therapy with ferric carboxymaltose (FCM) was shown to increase the concentration of circulating intact FGF23 (iFGF‐23),(3, 4, 5) but the long‐term effects of repeated iron infusions and prolonged hypophosphatemia have not been investigated. Here, FGF23 is linked to hypophosphatemia.