Evidence check: Transferrin in the context of Sport

Transferrin is a key protein for iron transport in the blood and is often used in sports contexts as a marker of iron status. Low transferrin levels can indicate iron deficiency anemia, which impairs endurance performance. However, the evidence for using transferrin alone as a direct biomarker for performance optimization is weak. Interpretation is complicated by factors such as inflammation, training load, and individual variability. Moreover, the provided context lacks specific studies or guidelines that support the evidence-based use of transferrin in sports. Therefore, a conservative assessment is warranted: transferrin can be useful as part of a comprehensive iron status panel (including ferritin, hemoglobin, soluble transferrin receptor), but isolated measurements are insufficient. Athletes with abnormal values should seek medical advice.