Iron is a fundamental trace element essential for the immune system, and current research on iron (Fe) supplements is increasingly focusing on food-derived peptides capable of binding iron ions. The objectives of this study were to characterize the iron-chelating peptide (Mytilus edulis protein hydrolysate, MEPH) derived from M. edulis and to investigate the effects of MEPH-Fe complexes on mice with iron deficiency-induced iron deficiency anemia (IDA). MEPH and iron (Ⅱ) sulfate heptahydrate successfully formed MEPH-Fe complexes under conditions of 4.5 mg/mL of concentration, 45 ℃, 60 min of incubation, and utilizing both carboxyl and amino binding sites. Compared to MEPH alone, the MEPH-Fe complexes exhibited fluorescence quenching, ultraviolet shifts, reduced X-ray diffraction (XRD) peak intensities, stabilization during in vitro digestion, microstructural changes, increased particle size, and decreased absolute values of Zeta potential. In the IDA mouse model, the MEPH-Fe complexes were able to restore body weight, hematological indices, organ coefficients, iron content in organs, and antioxidant capacity to normal levels. Additionally, they demonstrated beneficial effects on IDA-induced colonic inflammation by normalizing tumor necrosis factor-alpha (TNF-α) and interleukin-10 (IL-10) levels. The results indicated that MEPH-Fe complexes had more positive effects on IDA mice compared to ferrous sulfate. In conclusion, this study provides valuable insights into the potential of MEPH-Fe complexes as iron supplements.