Vitamins & minerals
Iron
Names you may see: ferrous sulfate fumarate gluconate bisglycinate elemental iron
The quick take
Iron is needed for haemoglobin, which carries oxygen in the blood, and for normal cellular function.
A closer look
What forms will I see on a label?
Common forms include ferrous sulfate, fumarate and gluconate. Compare elemental iron amounts; the compound weight is not the iron dose.
Why people use it
People use iron to address inadequate intake or confirmed deficiency. Fatigue and endurance concerns can prompt interest, but they have many possible causes.
These are common goals and marketing uses. The evidence section below explains what research supports.
What does the evidence tell us?
Correcting deficiency can help restore normal function. Extra iron does not provide a general energy or performance boost when iron status is adequate.
What should I know before using it?
Use supplements according to individual advice. Iron can cause digestive upset and dangerous overdose, especially in children. Keep it securely out of reach and avoid use with iron-overload conditions unless directed.
Sources & further reading
NIH Office of Dietary Supplements ↗
Content reviewed: September 30, 2026
General educational information. Follow the product label and seek individual advice when needed.