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Mineral

Iron

Iron is an essential mineral the body needs to make hemoglobin, the protein in red blood cells that carries oxygen.

Also listed as Ferrochel

FertilityEnergyEssential HealthStress & MoodCardiovascular

What it is studied for

The strongest rated effects first. Bars show the size of the effect, the letter grades the evidence, and each rating lists the studies behind it.

Pregnancy PrepFertilityStrongA3 studies
Energy CrashesEnergyStrongA3 studies
Essential HealthStrongA3 studies
Mood SupportStress & MoodModerateBNo linked study
Blood pressureCardiovascularNo effectFNo linked study
FatigueEnergyNot rated–No linked study
Every rating with its studiesGrouped by health goal, with the publications behind each rating

Why does iron matter for energy?

Iron is part of hemoglobin, the protein that carries oxygen in red blood cells, and myoglobin in muscle. Iron stores can fall before anemia, a low blood hemoglobin level, develops, so a normal hemoglobin result does not always mean stores are adequate. 1

What can a blood test tell you?

Ferritin helps assess stored iron, but inflammation can change the result. Clinicians often interpret several measurements together. Menstrual blood loss, pregnancy, and frequent blood donation are among the situations associated with greater risk of low iron. 1

Key studies

The most recent publications linked to Iron's ratings.

Daily oral iron supplementation during pregnancy.2024Iron deficiency anemia: a critical review on iron absorption, supplementation and its influence on gut microbiota.2024Iron Deficiency and Iron Deficiency Anemia: Potential Risk Factors in Bone Loss2023Iron Metabolism: Interactions with Energy and Carbohydrate Availability2020Energy deficit increases hepcidin and exacerbates declines in dietary iron absorption following strenuous physical activity: a randomized-controlled cross-over trial.2020
All 9 studiesEvery publication linked to Iron

Why people take it

Essential Health22.6%
Energy15.9%
Immune Support14.7%
Fitness9.6%
Bone & Joint9.6%
Gut Health7.2%

SuppCo community snapshot, 2026-09-28. Reasons for use are not evidence that it works.

Questions people ask

Can iron stores be low without anemia?

Yes. Stores can decline while hemoglobin remains in the normal range; ferritin is one part of the assessment. 1

Does fatigue mean I need iron?

The positive fatigue trial selected women with low ferritin. Its result cannot diagnose the cause of tiredness or establish benefit when stores are adequate. 2

Is plant iron useful?

Yes. Plant foods contain nonheme iron, whose absorption improves with vitamin C. 1

Is 40 mg an EU treatment dose?

No. It is EFSA’s safe level for total adult intake, with medically supervised treatment outside its scope. 3

Does iron help mood?

Depression and anxiety scores did not significantly improve in the 12-week fatigue trial. That finding should not be replaced by a general mood claim. 2

Sources

  1. Iron: Fact Sheet for Health Professionals NIH Office of Dietary Supplements

Further reading

Illustration for Iron.GuideFinding the right iron supplement: forms, dose and tolerabilityComparing ferrous sulfate, bisglycinate and other forms: elemental iron, dosing rhythm, blood tests and the limits of self-treatment.Read the article Illustration for Iron.GuideTransferrin saturation (TSAT)What transferrin saturation shows about available iron, how it is calculated, and why ferritin, inflammation and sampling conditions belong in the picture.Read the article Illustration for Iron.GuideNon-heme iron: foods, absorption and blood testsWhich foods supply non-heme iron, how vitamin C and meals affect its absorption, and what blood tests reveal about iron status.Read the article Illustration for Iron.GuideHow long do iron tablets take to work? Blood count, ferritin and symptomsWhen hemoglobin and iron stores change, why fatigue can linger, and how to monitor iron treatment sensibly.Read the article Illustration for Iron.GuideIron bisglycinate or ferrous sulfate: comparing effect and tolerabilityWhich differences between iron bisglycinate and ferrous sulfate matter, and why a gentler form is not automatically better for everyone.Read the article Illustration for Iron.GuideIron side effects: constipation, diarrhea and nauseaWhy oral iron supplements can upset the gut, and which changes to form, amount and dosing schedule can be discussed together.Read the article Illustration for Iron.GuideIron in pregnancy: needs, deficiency and safe supplementationWhy iron needs rise, which blood tests help, and how prevention, treatment, tolerability and the postpartum period fit together.Read the article Illustration for Iron.GuideWhen to take iron? Time of day, meals and your treatment planMorning or evening, with food or on an empty stomach: what really counts when taking iron, and which timing rules do not apply to everyone.Read the article Illustration for Iron.GuideIron deficiency anemia: what blood tests show about your iron statusWhich blood values point to iron deficiency anemia, how ferritin and transferrin saturation relate, and how inflammation, pregnancy and other factors change the picture.Read the article Illustration for Iron.GuideIron in the blood: what your iron level tells youHow to interpret serum iron, what role ferritin and inflammation play, and why time of day, diet and medications can affect the results.Read the article Illustration for Iron.GuideLow ferritin, normal ironNormal serum iron does not rule out empty iron stores. What low ferritin means, which symptoms are possible and how the cause is investigated.Read the article Editorial illustration of an oat grain opening into golden fibers and a blue ribbon.GuideWhich supplements can cause constipation?Calcium, iron and other products can change bowel habits. How to identify possible triggers and discuss changes that make sense.Read the article Editorial illustration of a dark metallic sphere in a warmly lit circular niche, a visual metaphor for iron reserves.GuideFerrous bisglycinate: absorption, side effects and how it compares with other forms of ironWhen ferrous bisglycinate may be an alternative, what elemental iron means, and how to follow a response to iron treatment.Read the article