AIM: To study the effect of dihydroquercetin on the indicators of oxidative metabolism in young athletes engaged in the winter sports in the Khanty-Mansiysk Autonomous Okrug (KhMAO).
 MATERIAL AND METHODS: The indicators of oxidative metabolism were studied in a group of 56 male students (mean age 19.300.51 years) from the Khanty-Mansiysk boarding school of the Olympic reserve. These students were actively involved in winter sports such as cross-country skiing and biathlon. To assess the impact of the plant-derived antioxidant bioflavonoid Baikal dihydroquercetin (DHQ), the participants were administered a daily dose of 120 mg of DHQ for a period of 60 days. Measurements were taken before and after the exposure. Blood lipid peroxidation (LPO) products were studied, namely, lipid hydroperoxides (LHP) and products that react with 2-thiobarbituric acid products (PR-TBA). Additionally, we examined the indicators of the body's antioxidant defense system (ADS) through the assessment of total antioxidant activity (TAA) and thiol status (TS). To quantify the overall oxidative stress experienced by the participants, we calculated the oxidative stress coefficient (OSC) using the formula: OSC = LHP PR-TBA / TAA TS.
 RESULTS: The average levels of LPO values (HPL and PR-TBA) among KhMAO athletes have surpassed the upper limit of optimal values. On the other hand, the ADS parameters (TAA and TS) fall within the range of physiologically optimal values, albeit closer to the lower limit. Notably, athletes have exhibited an OSC increase that is nearly 3.5 times higher than the maximum allowable value. A quarter of the individuals examined displayed elevated HPL values, while more than 30% showed increased PR-TBA levels. A third of male athletes exhibited reduced ADS values compared to the physiologically optimal range. In total, 70.4% of skiers and biathletes in KhMAO have exceeded the OSC parameters. After two months of daily intake of 120 mg DHQ, the normalization of indicators of oxidative metabolism was observed. All parameters aligned with physiologically optimal values, except for OSC. We found a decrease in primary (LHP, 1.15 times) and secondary (PR-TBA, p=0.046) LPO indicators parallel to a significant increase in ADS indicators, specifically TAA (p=0.022) and TS (p=0.049). Conversely, there was a significant increase in ADS indicators, specifically TAA (p=0.022) and TS (p=0.049).
 Despite these positive changes, the OSC value, although significantly reduced (p 0.001) by 2.3 times compared to the initial value, remained above the upper limit of the physiological norm.
 CONCLUSION: The study demonstrated that young athletes engaged in winter sports experienced improved indicators of oxidative metabolism after a consistent two-month intake of the potent antioxidant DHQ. This led to the restoration of a balanced prooxidant-antioxidant state, enhanced overall well-being, and expedited recovery following intense physical exertion. Furthermore, our results may suggest that DHQ may contribute to prevention of non-communicable diseases in the future.