Iron — Mechanism, Benefits, Dosing

Overview

Oxygen-carrying mineral central to hemoglobin and cellular respiration.

Natural sources

Red meat
Liver
Lentils
Spinach

Common forms

Bisglycinate (gentle)
Sulfate
Heme iron polypeptide

Forms & variants of Iron

Different chemical forms of Iron behave differently. Browse each form's mechanism, bioavailability, and best-use context.

Bisglycinate

Iron Bisglycinate

Chelated ferrous iron — best-tolerated form with high absorption and minimal GI distress.

Ferrous Sulfate

Standard low-cost iron salt — effective but commonly causes GI side effects.

Heme Iron

Heme Iron Polypeptide

Animal-source heme iron — absorbed via separate receptor, unaffected by phytates/calcium.

Mechanism of action

Hemoglobin/myoglobin oxygen binding; cofactor for cytochromes and many enzymes.

Pathways

· Oxygen transport
· ETC cytochromes

Effects on the body

Supports

Hemoglobin synthesis

Supports

Energy in iron-deficient

Organ system effects

Immune System

Critical for T-cell function.

Evidence-based benefits

Resolves iron-deficiency anemia

Strong evidence

Improves fatigue in low-ferritin women

Moderate evidence

Potential side effects

Common

· Constipation
· Nausea
· Black stools

Rare

· GI ulceration

Serious

· Toxic overdose (esp. children)
· Hemochromatosis worsening

Drug interactions

PPIs

Reduce absorption.

moderate

Levothyroxine

Separate 4 h.

moderate

Quinolones

Chelates antibiotic.

moderate

Safety & non-supplemental interactions

Educational summary — always confirm with your clinician or pharmacist before starting, stopping, or combining with prescription therapy.

Avoid with these conditions

·Hemochromatosis or iron overload
·Thalassemia
·Chronic liver disease
·Active infection (iron feeds pathogens)

Avoid / monitor with these medications

·Levothyroxine (separate by 4 h)
·Tetracyclines, fluoroquinolones (separate by 2 h)
·Levodopa, methyldopa
·Bisphosphonates
·Antacids and PPIs (reduce absorption)

Supplement interactions

Pairs well with

Vitamin C
Boosts non-heme iron absorption.

Avoid combining with

Calcium / coffee / tea
Reduce iron absorption.
Hemochromatosis
Iron overload risk.

Dosing & bioavailability

Typical dose

18 mg female / 8 mg male; 65 mg elemental for anemia

Timing

Alternate-day dosing increases absorption

Where to buy

Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

Mineral

Iron

Amazon

Wide selection · fast shipping

Mineral

Iron

iHerb

Global delivery · curated brands

Mineral

Iron

Thorne

Practitioner-grade · NSF tested

Scientific evidence (9)

Systematic reviewExamine.com Supplement Database · 2023

Iron: pharmacology, clinical evidence, and safety — narrative review

Examine.com Research Team

Curated narrative review of human and preclinical evidence for Iron, including mechanism, typical dosing, and safety considerations.

Key findings

Best-supported outcome: Resolves iron-deficiency anemia (evidence: strong). Additional outcomes and limitations summarized in the full profile.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Iron — Resolves iron-deficiency anemia

Live PubMed search

Live results for "Iron Resolves iron-deficiency anemia" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Iron and "Resolves iron-deficiency anemia". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Iron — Improves fatigue in low-ferritin women

Live PubMed search

Live results for "Iron Improves fatigue in low-ferritin women" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Iron and "Improves fatigue in low-ferritin women". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Iron — randomized controlled trial

Live PubMed search

Live results for "Iron randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Iron and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Iron — meta-analysis

Live PubMed search

Live results for "Iron meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Iron and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Iron — pharmacokinetics

Live PubMed search

Live results for "Iron pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Iron and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Iron — safety adverse events

Live PubMed search

Live results for "Iron safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Iron and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Iron — dose response

Live PubMed search

Live results for "Iron dose response" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Iron and "dose response". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewGoogle Scholar · 1970

Google Scholar: Iron — clinical evidence

Live Scholar search

Cross-database citation index for Iron as it relates to "clinical evidence".

Key findings

Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

Open study

Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.