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Heme Iron Polypeptide

Iron in the heme form from animal blood, sold as better absorbed and gentler. Randomized trials find it no better than ferrous salts on haemoglobin or ferritin, at many times the price.

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What the science says

  • No better on the outcomes that matter Moderate evidence

    A 2025 randomized trial in 208 anemic infants found no difference from ferrous sulfate in the primary endpoints of haemoglobin and ferritin after 84 days, although several secondary markers (serum iron, transferrin saturation) favoured heme iron.

  • Small kidney-disease trial Limited evidence

    In 40 patients with non-dialysis chronic kidney disease, oral heme iron polypeptide maintained haemoglobin similarly to intravenous iron sucrose over 6 months, but ferritin rose far less (85 vs 244 µg/L). The trial was small and unblinded.

  • The tolerability claim is not demonstrated Limited evidence

    In both trials adverse events did not differ significantly between heme iron and its comparator, so the "gentler on the stomach" selling point rests largely on the much smaller amount of elemental iron each capsule delivers.

Dosage & safety

Studied doseProducts typically supply 11 mg heme iron polypeptide (roughly 1–2 mg elemental heme iron) taken one to three times daily — a fraction of the elemental iron in a standard ferrous salt.
SafetyGenerally well tolerated. Derived from bovine blood, so unsuitable for vegetarians and vegans and for some religious diets. Iron should not be supplemented without a confirmed deficiency; avoid in haemochromatosis. If anemia is significant, the low elemental dose may simply be inadequate.

How to take it

TimingSplit the daily amount into two or three doses across the day rather than taking it all at once.
With food?It can be taken with food, since heme iron is absorbed by a different route than iron salts and is far less blocked by meals, tea or coffee.
Worth knowingGet a ferritin test before and after a few months of use, because the elemental iron here is low enough that it may not correct a real deficiency.

Interactions

With medications

  • levothyroxine and other thyroid hormone

    Iron binds levothyroxine in the gut and reduces how much is absorbed. separate by at least 4 hours

  • tetracycline and quinolone antibiotics (doxycycline, ciprofloxacin)

    Iron and the antibiotic form a complex that neither absorbs well. separate by at least 2 hours

  • bisphosphonates (alendronate, risedronate)

    Iron reduces absorption of the bisphosphonate. take the bisphosphonate first thing in the morning and the iron at a different time of day

With other supplements

  • calcium supplements

    Calcium competes with iron and lowers the amount absorbed from a single dose. take them at different meals

  • zinc supplements

    Large doses of iron and zinc compete for the same absorption pathways. separate by at least 2 hours

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Is heme iron polypeptide better absorbed than regular iron pills?

Not in a way that matters: a randomized trial in 208 anemic infants found heme iron polypeptide no better than ferrous sulfate on haemoglobin or ferritin after 84 days, though some secondary markers favoured it. You pay many times the price for no demonstrated advantage on the outcomes that count.

Is heme iron polypeptide gentler on the stomach?

That selling point is not demonstrated (limited evidence). In the trials, side effects of heme iron polypeptide did not differ from the comparator, and any gentleness likely reflects the much smaller amount of elemental iron each capsule delivers.

How much heme iron polypeptide should you take per day?

Products typically supply 11 mg heme iron polypeptide (roughly 1–2 mg elemental iron) taken one to three times daily, split across the day. That is a fraction of a standard ferrous salt, so check ferritin before and after a few months to see whether heme iron polypeptide is actually correcting a deficiency.

Can you take heme iron polypeptide with levothyroxine?

Separate them by at least 4 hours, because the iron in heme iron polypeptide binds levothyroxine in the gut and reduces its absorption. Keep it at least 2 hours apart from tetracycline or quinolone antibiotics as well.

Scientific references

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