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Iron — Frequently Asked Questions

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Frequently Asked Questions

Should I take iron every day or every other day?

Recent research from ETH Zurich (Stoffel et al., 2020) found that alternate-day iron dosing improves fractional absorption by about 40% compared to daily dosing. This is because iron triggers hepcidin release, which blocks absorption for about 24 hours. For non-anemic iron deficiency, every-other-day dosing is now recommended by many hematologists.

How do I know if I need iron supplements?

Only take iron supplements if blood tests confirm deficiency. Key tests include serum ferritin (below 30 ng/mL indicates depletion), transferrin saturation, and hemoglobin. Symptoms of deficiency include fatigue, pale skin, brittle nails, and cold hands/feet. Never self-prescribe iron, as excess iron causes oxidative damage.

Why does iron cause constipation and how can I prevent it?

Iron causes constipation because unabsorbed iron in the gut alters the microbiome and reduces intestinal motility. To minimize this: use ferrous bisglycinate (much gentler), take with vitamin C to improve absorption (less unabsorbed iron), try every-other-day dosing, and increase fiber and water intake.

Full Iron Guide

References

  1. (). Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial. CMAJ. DOI
  2. (). Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split doses. The Lancet Haematology. DOI
  3. (). Iron deficiency. The Lancet. DOI