Ferric citrate

MineralIron

What is it

Ferric citrate is an iron salt containing iron in the ferric (Fe3+) form complexed with citrate. It is used both as an iron supplement and as a prescription phosphate binder/iron replacement (Auryxia, Ferracru) for chronic kidney disease patients.

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Iron deficiency anemia in CKD

Strong Evidence

Ferric citrate is FDA-approved for both serum phosphate control and iron deficiency anemia in CKD. Strong evidence in this specific population.

General iron supplementation

Good Evidence

Ferric forms are generally less efficiently absorbed than ferrous salts (sulfate, fumarate, gluconate). Ferric citrate works but is not first-line for routine iron deficiency.

How it works

When taken orally, ferric citrate dissociates in the GI tract. The ferric iron is reduced to ferrous (Fe2+) form for absorption by intestinal enterocytes via DMT1, though ferric forms are generally less efficiently absorbed than ferrous forms. The citrate component binds phosphate in the intestine, reducing phosphate absorption — useful in chronic kidney disease where serum phosphate tends to be elevated. In CKD, this dual effect (provides absorbable iron + lowers phosphate) makes ferric citrate a useful prescription option.

Dosage

Prescription Auryxia: 2 g (2 tablets) three times daily with meals, titrated by labs. OTC iron supplement doses vary. Always personalize with iron studies.

When and how to take it

Prescription form: with meals. Iron supplements generally absorb better on empty stomach but cause more GI upset; take with food if needed. Vitamin C improves absorption; avoid calcium/coffee/tea concurrently.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Ferric citrate (prescription)

FDA-approved prescription product for CKD patients.

Iron absorption ~10-30% in fasted state.

OTC iron supplement

Found in some multivitamin and iron products.

Comparable to other ferric salts.

Safety

Common side effects: diarrhea, dark stools, nausea, constipation. Hyperkalemia and hypocalcemia have been reported. Iron toxicity is a risk with overdose, especially in children. Keep out of reach.

Who should be cautious

Iron overload disorders (hemochromatosis) should avoid iron supplementation. Use only with appropriate iron studies if not on physician guidance. Use cautiously in active GI bleeding.

Interactions

Reduces absorption of fluoroquinolones, tetracyclines, levothyroxine, mycophenolate, doxycycline (separate by 2-4 hours). Phosphate binding can affect vitamin D activation and absorption of phosphate-containing drugs.

Food sources

Not a typical food

Amount
N/A
%DV
—

Frequently asked questions

Is ferric citrate better than ferrous sulfate?⌄

For general iron deficiency, ferrous sulfate is more absorbable. Ferric citrate has a specific role in chronic kidney disease where it also lowers phosphate.

References

Ferric citrate on Wikidata — Wikidata link

Ferric citrate on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Ferric citrate (PubMed search) — PubMed link

Track Ferric citrate with Pilora

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.