Iron

Iron supplementation · Ferrous Sulfate · Ferrous Fumarate · Ferrous Gluconate

Snapshot

Indications	Contraindications
Iron deficiency¹ Iron deficiency anemia¹ Maternal anemia prevention² Fatigue in iron deficiency³ Iron deficiency in heart failure⁴ Iron loss after blood donation⁵	Hereditary hemochromatosis⁵ Milk or soy allergy⁶

Iron is an essential mineral that carries oxygen as a component of hemoglobin and supports muscle metabolism through myoglobin⁵. Supplementation is used to restore depleted stores in iron deficiency and iron deficiency anemia, to prevent maternal anemia in pregnancy, and to ease fatigue and exercise limitation in menstruating women. Typical patients are women with heavy menstrual bleeding, pregnant women, and people with malabsorption or chronic inflammatory disease¹. Frequent blood donors are also at increased risk of deficiency⁵.

A United States Preventive Services Task Force evidence review found that pregnancy health outcomes beyond anemia showed no benefit or limited data⁷. In a 2025 observational study of Swedish teenage girls, vegetarian and vegan diets were associated with more iron deficiency than omnivore diets⁸. Ferrous and ferric salts are the most common supplement forms⁵, and 26154 products list iron; see Form comparison.

Hereditary hemochromatosis is the main reason to withhold iron: the condition predisposes to excessive absorption, and liver disease guidance for its management includes avoiding iron supplements⁵. Levodopa and levothyroxine labels warn that iron reduces their absorption⁵.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

84 sources, 72 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources