Ferrous Sulfate vs Heme Iron Polypeptide
How ferrous sulfate and heme iron polypeptide differ in elemental content, absorption, tolerance, and cost.
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Side by Side
| Ferrous Sulfate | Heme Iron Polypeptide | |
|---|---|---|
| Elemental content | 20% elemental iron | Varies by product |
| Absorption | High | High |
| How it is absorbed | Ferrous (Fe2+) iron is absorbed by divalent metal transporter 1 (DMT1) in the duodenum. Absorption rises when stores are low and falls as hepcidin rises after a dose. | Iron bound in the heme ring, absorbed intact through a separate heme pathway. Absorption is much less affected by phytates, calcium, and tea than non-heme iron. |
| Typical dose | 40-65 mg elemental iron daily or on alternate days for deficiency | Product-specific; per-tablet iron is low |
| Common uses | iron deficiency anemia, first-line oral repletion | GI intolerance to iron salts, maintenance after repletion |
| Side effects | Nausea, constipation, dark stools, epigastric pain; dose-dependent. | Low GI side effect rate at the low doses used. |
| Cost | Low | High |
| Also called | iron sulfate | heme iron, HIP |
When to Choose Ferrous Sulfate
Choose ferrous sulfate when you want the cheapest proven repletion and tolerate it. The reference form against which others are compared. A single morning dose on alternate days improved fractional absorption versus daily dosing in Stoffel 2017.
Ferrous Sulfate
The reference standard: cheapest, best studied, and the form used in the hepcidin dosing trials. GI side effects are the price.
What to look for: 65 mg elemental iron (325 mg tablet), not enteric coated, taken once in the morning on alternate days.
Find on iHerb Affiliate linkWhen to Choose Heme Iron Polypeptide
Choose heme iron polypeptide when you need iron that is less affected by meals and tolerate only low doses. Derived from animal hemoglobin; not vegetarian.
Heme Iron Polypeptide
Choose heme iron polypeptide when you need iron that is less affected by meals and tolerate only low doses.
What to look for: Heme Iron Polypeptide named on the Supplement Facts panel, with the amount per serving stated.
Find on iHerb Affiliate linkProducts on Titrate
15,991 of the 214,745 labels in the NIH Dietary Supplement Label Database list iron as an active ingredient (8,640 on market). 1,146 are sold as iron products by name.
Iron does not have its own search category yet. Each product above links to its full label in the NIH database.
Related
References
NIH Office of Dietary Supplements. Iron: Fact Sheet for Health Professionals.
Hallberg L, Brune M, Rossander L. Iron absorption in man: ascorbic acid and dose-dependent inhibition by phytate. Am J Clin Nutr. 1989;49(1):140-144.
Moretti D, et al. Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women. Blood. 2015;126(17):1981-1989.
Tolkien Z, et al. Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysis. PLoS One. 2015;10(2):e0117383.
Stoffel NU, et al. 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. Lancet Haematol. 2017;4(11):e524-e533.
Stoffel NU, et al. Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women. Haematologica. 2020;105(5):1232-1239.
World Health Organization. WHO guideline on use of ferritin concentrations to assess iron status in individuals and populations. Geneva: WHO; 2020.