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minerals⭐ Popular

Iron(II) fumarate

Also known as:Ferrous fumarateIron(II) fumarateFe(II) fumarateIron(2+) fumarateEisen(II)-fumarat (German)Iron fumarateIron bis(fumarate)

💡Should I take Ferrous Fumarate?

Ferrous fumarate is a pharmaceutical-grade iron(II) organic salt — molecular formula C₄H₂FeO₄, CAS 141-01-5 — containing approximately 33% elemental iron by weight, the highest among common oral ferrous salts. Used clinically since the mid-20th century, it serves as a first-line oral treatment for iron deficiency anemia (IDA) and prophylaxis during pregnancy, where the daily requirement rises to 27 mg elemental iron. Absorbed primarily in the duodenum via the DMT1 transporter, ferrous fumarate delivers bioavailable Fe²⁺ that is subsequently oxidized, bound to transferrin, and delivered to bone marrow for hemoglobin synthesis. Hemoglobin typically begins rising within 1–3 weeks of therapy; full store repletion requires 3–6 months. Gastrointestinal side effects — nausea (10–30%), constipation (10–20%), and dark stools — are the primary limitation, managed by dose adjustment or co-administration with food. Critical drug interactions include levothyroxine (separate by 4 hours), tetracyclines (separate by 2–6 hours), and fluoroquinolones. Absolute contraindications include hereditary hemochromatosis and known iron overload disorders. For US consumers, look for USP Verified or NSF-certified products with clearly labeled elemental iron content.

Everything About Ferrous Fumarate

Science-Backed Benefits

Treatment of iron deficiency anemia (IDA)

✓ Strong Evidence

Supplies bioavailable ferrous iron for incorporation into heme synthesis in erythroblasts, restores hemoglobin concentration and oxygen-carrying capacity.

Prevention of iron deficiency during pregnancy

✓ Strong Evidence

Provides supplemental elemental iron to meet increased maternal and fetal iron demands, preventing maternal anemia and associated maternal/fetal complications.

Improvement in fatigue and functional capacity associated with iron deficiency (with/without anemia)

◐ Moderate Evidence

Correcting iron deficiency restores function of iron-dependent enzymes (mitochondrial cytochromes, oxidative phosphorylation), increases hemoglobin and oxygen delivery and improves energy metabolism.

Improved exercise capacity in athletes with iron deficiency or iron-restricted erythropoiesis

◐ Moderate Evidence

Repletion of iron enhances oxygen delivery via increased hemoglobin and supports myoglobin and mitochondrial enzymes in muscle.

Improvement of cognitive function in infants and children with iron deficiency

◐ Moderate Evidence

Iron is crucial for brain development, myelination, and neurotransmitter synthesis; repletion can prevent progressive deficits.

Reduction in restless legs syndrome (RLS) symptoms when linked to iron deficiency

◐ Moderate Evidence

Brain iron deficiency (low CNS ferritin) implicated in RLS pathophysiology; replenishment of systemic iron can increase CNS iron over time and reduce symptoms in iron-deficient individuals.

Support for postpartum recovery following pregnancy-associated iron loss

✓ Strong Evidence

Repletes depleted iron stores after delivery, supports lactation-related metabolic needs and maternal energy.

Adjunct to erythropoiesis-stimulating therapies (ESAs) in chronic kidney disease or oncology

✓ Strong Evidence

Correcting iron deficiency optimizes response to ESAs by ensuring iron substrate availability for increased erythropoiesis.

📋 Basic Information

Classification

Mineral (iron salt) — Iron(II) organic salt; oral iron supplement; pharmaceutical excipient active ingredient

Active Compounds

  • • Immediate-release tablet (ferrous fumarate)
  • • Capsule (powder-filled; ferrous fumarate)
  • • Coated/enteric tablet (ferrous fumarate; less common)
  • • Oral suspension/syrup
  • • Combination tablets (ferrous fumarate with folic acid, vitamin C, or multivitamins)

Alternative Names

Ferrous fumarateIron(II) fumarateFe(II) fumarateIron(2+) fumarateEisen(II)-fumarat (German)Iron fumarateIron bis(fumarate)

Origin & History

Iron-containing mineral preparations have been used traditionally to treat 'blood weakness' and fatigue; these traditional uses are nonspecific and predate modern chemistry. There is no widely documented traditional use specific to ferrous fumarate as an isolated compound.

🔬 Scientific Foundations

⚡ Mechanisms of Action

Enterocytes (duodenal/jejunal epithelial cells) — primary site of uptake via DMT1., Erythroid precursor cells in bone marrow — iron used for heme synthesis via ferrochelatase., Hepatocytes and macrophages — storage as ferritin; involvement in systemic iron regulation via hepcidin.

💊 Available Forms

Immediate-release tablet (ferrous fumarate)Capsule (powder-filled; ferrous fumarate)Coated/enteric tablet (ferrous fumarate; less common)Oral suspension/syrupCombination tablets (ferrous fumarate with folic acid, vitamin C, or multivitamins)

✨ Optimal Absorption

Ferrous (Fe2+) is taken up across apical enterocyte membranes via DMT1 (divalent metal transporter 1) following reduction (if necessary) of dietary ferric (Fe3+) to ferrous by duodenal cytochrome b (Dcytb)/gastric acid. Inside enterocytes, iron is either stored in ferritin or exported via ferroportin across the basolateral membrane and oxidized to Fe3+ for binding to transferrin in plasma.

Dosage & Usage

💊Recommended Daily Dose

Prophylactic Adult Men: 8 mg elemental iron/day (DRI) • Prophylactic Adult Women Nonpregnant: 18 mg elemental iron/day (DRI) • Pregnancy Recommendation: 27 mg elemental iron/day (DRI for pregnant women) • Therapeutic For IDA Adults: 50–200 mg elemental iron/day (commonly 100–200 mg elemental iron total, typically divided into 1–3 doses depending on regimen)

⏰Timing

Preferably taken on an empty stomach for maximal absorption (e.g., morning 1 hour before meals or 2 hours after), but GI intolerance commonly requires taking with food. — With food: If GI side effects are significant, take with a small amount of food that does not contain inhibitors (avoid milk/tea/coffee/calcium-rich foods). — Gastric acidity favors dissolution and absorption; food and some beverages contain inhibitors (phytates, polyphenols), while ascorbic acid increases absorption.

Oral iron preparations: gastrointestinal adverse events and disproportionality analysis in FAERS

2024-10-01

A study analyzing FAERS data found ferrous fumarate has the weakest gastrointestinal adverse event disproportional reporting signal (ROR = 0.36) among oral iron preparations, with no positive signals detected. This aligns with clinical evidence of minimal gastrointestinal effects. The research confirms ferrous fumarate's favorable tolerability profile.

📰 PMCRead Study↗

Glycoprotein Matrix-Bound Iron Improves Absorption Compared to Ferrous Bisglycinate Chelate and Ferrous Fumarate: A Randomized Crossover Trial

2025-08-15

This randomized crossover trial demonstrates that glycoprotein matrix-bound iron offers superior absorption compared to ferrous bisglycinate chelate and ferrous fumarate. The study highlights differences in bioavailability among iron supplements. Published in a peer-reviewed journal, it provides evidence for optimizing iron supplementation strategies.

📰 CureusRead Study↗

Effect of iron supplements on cognitive development in children

2026-01-10

This umbrella review synthesizes evidence on iron supplementation, including ferrous fumarate, and its impact on child cognitive development. Meta-analyses show varied effects across neurodevelopmental domains, with calls for standardized RCTs to address heterogeneity. It identifies gaps in dosage and duration protocols for future research.

📰 Frontiers in NutritionRead Study↗

Safety & Drug Interactions

⚠️Possible Side Effects

  • •Nausea
  • •Abdominal pain/cramps
  • •Constipation
  • •Diarrhea
  • •Dark (black) stools (oxidized iron)
  • •Metallic taste

💊Drug Interactions

medium–high

Reduced absorption of antibiotic (chelation in GI tract); reduced absorption of iron similarly.

Moderate

Reduced antibiotic absorption/effectiveness due to chelation.

Moderate

Reduced absorption of bisphosphonate and/or increased GI irritation risk.

high (clinically significant)

Reduced levothyroxine absorption → reduced thyroid hormone effect.

medium–high (especially with chronic PPI use)

Reduced iron absorption

Moderate

Reduced iron absorption

low–medium

Potential alteration in absorption and pharmacodynamics (clinical relevance variable).

Low

Pharmacodynamic interaction possible via CNS neurotransmitter changes if iron status changes drastically.

🚫Contraindications

  • •Hereditary hemochromatosis (known iron overload syndromes)
  • •Primary hemosiderosis or known iron overload conditions
  • •Hypersensitivity/allergy to ferrous fumarate or any excipient in the formulation

Important: This information does not replace medical advice. Always consult your physician before taking dietary supplements, especially if you take medications or have a health condition.

🏛️ Regulatory Positions

🇺🇸

FDA (United States)

Food and Drug Administration

Iron salts (including ferrous fumarate) are permitted as dietary supplements when labeled appropriately and complying with DSHEA. Therapeutic claims (treatment of disease) require drug approval. FDA enforces regulations regarding labeling, safety reporting, and manufacturing standards for marketed products. The FDA issues specific warnings and guidelines about pediatric accidental ingestion of iron-containing supplements given high toxicity risk in children.

🔬

NIH / ODS (United States)

National Institutes of Health – Office of Dietary Supplements

The NIH Office of Dietary Supplements (ODS) provides fact sheets on iron (including recommended dietary allowances, sources, interactions, and safety guidance). NIH/ODS recognizes ferrous salts as common supplemental forms and notes the importance of monitoring iron status and avoiding unnecessary supplementation in individuals without deficiency.

⚠️ Warnings & Notices

  • •Keep iron supplements out of reach of children; accidental ingestion is a major cause of pediatric poisoning.
  • •Do not exceed recommended therapeutic doses without medical supervision due to toxicity risk.
  • •Use with caution in individuals with conditions predisposing to iron overload (e.g., hemochromatosis).
✅

DSHEA Status

Subject to DSHEA when marketed as a dietary supplement; as an active therapeutic agent (claims to treat iron-deficiency anemia) iron products may be prescription or OTC drugs depending on formulation and labeling.

FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease.

🇺🇸 US Market

📊

Usage Statistics

National usage varies by population subgroup; many pregnant women and older adults take iron-containing supplements. Precise up-to-date prevalence estimates require access to current NHANES/market research datasets. Historically, iron supplement use is common in prenatal populations and among individuals with diagnosed iron deficiency anemia.

📈

Market Trends

Sustained demand for prenatal iron-containing multivitamins; growth in interest for better-tolerated iron formulations (e.g., iron bisglycinate, ferric maltol, liposomal iron); increasing attention to alternate-day dosing and hepcidin-informed regimens; growth of online direct-to-consumer supplement sales.

💰

Price Range (USD)

Budget: $15–25/month; Mid: $25–50/month; Premium/specialty formulations: $50–100+/month (varies by formulation, dosage, brand, and third-party certification).

Note: Prices and availability may vary. Compare multiple retailers and look for quality certifications (USP, NSF, ConsumerLab).

⚕️Medical Disclaimer

This information is for educational purposes only and does not replace advice from a qualified physician or pharmacist. Always consult a healthcare provider before taking dietary supplements, especially if you are pregnant, nursing, taking medications, or have a health condition.

📚Scientific Sources

Last updated: February 22, 2026