SELECTED DIETARY SUPPLEMENTS AND THEIR IMPACT ON ENDURANCE AND RECOVERY IN RUNNERS: A SYSTEMATIC REVIEW

Running places high metabolic, neuromuscular and physiological demands on athletes, stimulating interest in nutritional supplements that may enhance performance and delay fatigue. Various ergogenic aids - including caffeine, creatine, β-alanine and beetroot-derived nitrates, have been investigated, yet their relative effectiveness across different running modalities remains unclear. A systematic search of PubMed (2010–2025) using the terms “supplementation” and “running” identified 234 records. After screening titles, abstracts and full texts according to predefined criteria, 26 studies evaluating single-ingredient supplements and reporting running-specific outcomes were included. A narrative synthesis was conducted due to heterogeneity in study designs and performance tests. Caffeine consistently improved running performance across sprint, repeated and endurance efforts by extending time to exhaustion, enhancing acceleration and increasing metabolic activation without elevating physiological strain. Creatine improved mean power, maintained running speed and reduced fatigue during short and repeated high-intensity efforts, with limited effects in endurance running. β-alanine increased muscle carnosine content and enhanced tolerance to high-intensity or fatigue-inducing exercise, while producing modest improvements during submaximal workloads. Beetroot-derived nitrates improved performance primarily in short, intense and intermittent running, especially in moderately trained athletes, whereas betalains supported recovery through antioxidant and anti-inflammatory mechanisms. Caffeine, creatine, β-alanine and beetroot-derived supplements all exert ergogenic effects, but their benefits are exercise-specific. Matching the supplement to the running demands and athlete characteristics is essential for maximizing performance outcomes.