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917 studies

Iron

Last reviewed: 3/2/2026

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Absorption
Take with vitamin C to enhance absorption. Avoid taking with tea, coffee, or calcium supplements which inhibit absorption. Heme iron (from animal sources) is better absorbed.
Daily Dose
Common dose: 20–30 mg daily in supplementation for deficiency.
RDA: 18 mg for adult women; 8 mg for adult men. RDA varies by age and sex.
Upper limit: 45 mg per day for adults.
Best form: Ferrous sulfate or ferrous gluconate preferred.
Timing: On an empty stomach or with vitamin C to enhance absorption.
Excessive iron intake can lead to toxicity. Blood testing recommended before high-dose supplementation.
Food Sources
  • Red meat2.7mg per 100g
  • Lentils3.3mg per 100g
  • Spinach2.7mg per 100g

Not medical advice