General Dosage
18-65mg elemental iron daily for deficiency correction; 8-18mg for maintenance
Maximum dose: 45mg/day elemental iron for adults (NIH UL); therapeutic doses up to 65mg under medical supervision
Iron Dosage Guide
Evidence:Strong
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Dosage Recommendations
General recommendation: 18-65mg elemental iron daily for deficiency correction; 8-18mg for maintenance
Timing: On an empty stomach for best absorption; with vitamin C to enhance absorption; avoid with tea, coffee, dairy, or calcium within 2 hours
Dosage by Condition
Iron-deficiency anemia
65mg elemental iron 1-2x dailyStrong
Non-anemic iron deficiency
25-45mg elemental iron daily or every other dayStrong
Pregnancy
27-60mg elemental iron daily per WHO guidelinesStrong
Athletic performance
25-45mg daily for iron-depleted athletesModerate
| Condition | Recommended Dose | Evidence |
|---|---|---|
| Iron-deficiency anemia | 65mg elemental iron 1-2x daily | Strong |
| Non-anemic iron deficiency | 25-45mg elemental iron daily or every other day | Strong |
| Pregnancy | 27-60mg elemental iron daily per WHO guidelines | Strong |
| Athletic performance | 25-45mg daily for iron-depleted athletes | Moderate |
Upper limit: 45mg/day elemental iron for adults (NIH UL); therapeutic doses up to 65mg under medical supervision
Timing & Absorption
On an empty stomach for best absorption; with vitamin C to enhance absorption; avoid with tea, coffee, dairy, or calcium within 2 hours
Can be taken with or without food.
References
- RCTVaucher P, Druais PL, Waldvogel S, Favrat B (2012). Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial. CMAJ. DOI PubMed
- RCTStoffel NU, Cercamondi CI, Brittenham G, et al. (2017). Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women: two open-label, randomised controlled trials. The Lancet Haematology. DOI PubMed
- Meta-analysisRehman T, Agrawal R, Ahamed F, Das S, et al. (2025). Optimal dose and duration of iron supplementation for treating iron deficiency anaemia in children and adolescents: A systematic review and meta-analysis.. PloS one. DOI PubMed
- Watt A, Eaton H, Eastwick-Jones K, Thomas ET, et al. (2025). The benefits and harms of oral iron supplementation in non-anaemic pregnant women: a systematic review and meta-analysis.. Family practice. DOI PubMed
- Meta-analysisFiani D, Chahine S, Zaboube M, Solmi M, et al. (2025). Psychiatric and cognitive outcomes of iron supplementation in non-anemic children, adolescents, and menstruating adults: A meta-analysis and systematic review.. Neuroscience and biobehavioral reviews. DOI PubMed
- Meta-analysisFinkelstein JL, Cuthbert A, Weeks J, Venkatramanan S, et al. (2024). Daily oral iron supplementation during pregnancy.. The Cochrane database of systematic reviews. DOI PubMed
- Garofalo V, Condorelli RA, Cannarella R, Aversa A, et al. (2023). Relationship between Iron Deficiency and Thyroid Function: A Systematic Review and Meta-Analysis.. Nutrients. DOI PubMed