Iron Supplementation for Endurance Athletes
One pill of iron bis-glycinate (ferrochel) is likely insufficient to significantly improve ferritin levels for high-level endurance performance.
Optimal Iron Supplementation for Athletes
Iron supplementation is a common practice among endurance athletes due to concerns about iron deficiency affecting performance. However, the dosing needs to be appropriate to achieve meaningful results:
Recommended Dosing
- According to the 2024 AGA Clinical Practice Update, ferrous bis-glycinate contains approximately 25 mg of elemental iron per tablet 1
- For treating iron deficiency, guidelines recommend a daily dose of at least 200 mg of elemental iron for adults 1
- This would translate to multiple tablets of ferrochel being required to reach therapeutic levels
Effectiveness for Athletic Performance
- Research specifically examining ferritin levels and endurance performance shows that iron supplementation can raise serum ferritin levels, but increases in ferritin alone (without increases in hemoglobin) have not been consistently shown to improve endurance performance 2
- Athletes with low ferritin but normal hemoglobin may still benefit from supplementation, especially if hemoglobin is in the low-normal range 2
Comparing Iron Formulations
Ferrous bis-glycinate (ferrochel) has some advantages but still requires adequate dosing:
Ferrous Bis-glycinate Benefits
- Generally recognized as safe (GRAS) by the FDA 3
- May be better tolerated than other iron formulations with fewer gastrointestinal side effects 1, 4
- Has demonstrated safety even at high doses in toxicology studies 3
Comparative Effectiveness
- In a study comparing ferrous bis-glycinate with ferrous sulfate for pregnant women, 25 mg of elemental iron from bis-glycinate was as effective as 50 mg from ferrous sulfate 4
- However, another study in gastrectomized patients found that ferrous sulfate (80 mg elemental iron twice daily) produced better hematologic results than ferrous glycinate chelate (50 mg elemental iron daily) 5
Monitoring and Adjusting Supplementation
For athletes seeking to optimize iron status:
Assessment Parameters
- Monitor both ferritin and hemoglobin levels, as both are important for endurance performance 2
- Serum transferrin receptor concentrations may help identify true iron deficiency in athletes 6
- Consider that exercise-induced physiological changes can mimic iron deficiency and decrease hemoglobin and ferritin concentrations 6
Cautions
- Indiscriminate iron supplementation carries risks, including potential hemochromatosis in genetically susceptible individuals 6
- Elite athletes who have used long-term iron supplementation often have increased iron stores, which may be problematic 6
Bottom Line for Athletes
For high-level endurance athletes concerned about iron status:
- One pill of ferrochel (25 mg elemental iron) is likely insufficient for meaningful improvement in ferritin levels
- Multiple pills or a higher-dose formulation would be needed to reach therapeutic levels
- Monitor both ferritin and hemoglobin levels to assess effectiveness
- Consider that improved ferritin levels alone may not translate to improved performance unless hemoglobin was also deficient
If iron deficiency is confirmed, a more substantial supplementation regimen should be considered, potentially with multiple daily doses of ferrochel or an alternative iron formulation that provides higher elemental iron content.