Today, sports anemia occurs in elite sports quite often, although it is not a disease (does not apply to ICD-10), but only a pathological condition. Sports anemia is characterized by changes in the red link of the blood, and it is associated with a decrease in the content of erythrocytes and / or hemoglobin. However, this condition leads to a significant decrease in physical performance, and, consequently, the effectiveness of the competitive activity of representatives, first of all, of cyclic sports. Athletes are more sensitive to the effects of anemia and iron deficiency than people who are not constantly exposed to intense physical activity, since performance depends on the maximum oxygen consumption and utilization of active muscles. Sports anemia is often iron deficient, as well as B12 and folate deficient. Therefore, the assessment of various factors accompanying the development of anemia and the development of technologies for the correction of this pathological condition is an important task of sports laboratory diagnostics, as well as pharmacology and nutritional science of sports. Material and methods. We conducted a randomized, double-blind, placebo-controlled study to assess the safety and effectiveness of the effect of a course use of the Santeferra dietary supplement containing liposomal ferric iron in the form of pyrophosphate, vitamins B9, B12 and ascorbic acid on the results of training activities of representatives of cyclic sports with predominantly an aerobic energy supply mechanism. In the course of a dynamic study, which lasted 60 days, the parameters of hematological homeostasis and accumulation, metabolism and transport of iron (content of serum iron, transferrin, ferritin, folic acid, iron binding capacity of serum, saturation of transferrin with iron), as well as the level of serum erythropoietin and the severity of oxidative stress were assessed directly in the membranes of erythrocytes. In parallel, we determined the indicators of aerobic endurance: the absolute and relative values of the maximum oxygen consumption and the PWC170 value. Results and discussion. We found out that in the study sample of 67 athletes who specialized in sports with aerobic energy supply (running disciplines of athletics, rowing and canoeing, triathlon, cross-country skiing), 19 (28.35%) had manifestations of sports anemia, and 23 (34.32%) had latent iron deficiency, which also negatively effect on their physical performance. The course application of Santefrerra, 1 capsule per day for 60 days, helped to normalize the accumulation, transport and metabolism of iron, as well as to significantly reduce the manifestations of oxidative stress that occurs under the influence of prolonged physical exertion. In athletes with anemia and latent iron deficiency, practically no changes in the content of erythropoietin in the blood serum were found. At the end of the course of taking a dietary supplement, the indicators of the relative maximum oxygen consumption in the athletes of the main group increased by 11.5% (P <0.05) and the results of the PWC170 test by 11.4% (P <0.05) which displays predominantly aerobic endurance. In the placebo-control groups, we noted no positive dynamics in indicators of the red link of hematological homeostasis and the accumulation, metabolism and transport of iron, as well as the parameters of the prooxidant-antioxidant balance directly in the erythrocyte membranes during the 60-day observation period. Indicators of aerobic endurance also remained unchanged. Conclusion. Thus, the course using Santeferra is not accompanied by the development of side effects and is effective for the treatment of iron deficiencies in athletes