Iron plays a pivotal role in hematopoiesis, particularly in hemoglobin synthesis and oxygen transport. Alterations in iron availability, whether nutritional or pharmacological, directly influence erythroid indices and red blood cell morphology. This study employed validated UV–Vis spectrophotometric methods combined with hematological analysis to evaluate the effects of iron-containing substances, with and without caffeine, on complete blood count (CBC) parameters. Calibration results confirmed