Iron

Iron carries oxygen in the blood and supports energy metabolism. Deficiency is common, especially with heavy menstrual bleeding, pregnancy, restricted diets or blood loss, and it is the reason most people look up iron. Iron is also genuinely dangerous in overdose, particularly for young children.

Supplemental iron comes as ferrous (2+) or ferric (3+) salts and as chelates such as bisglycinate. Ferrous forms are generally better absorbed than ferric forms. Absorption from plant foods and from supplements is lower than from meat.

Iron is built into haemoglobin in red blood cells and into myoglobin and several enzymes, allowing oxygen transport and energy production.

Oral iron reliably corrects iron-deficiency anaemia when it is taken long enough and absorption is adequate. In pregnancy, supplementation reduces anaemia and low iron stores. Trials in people who are tired but not iron-deficient show inconsistent results, and supplementing without deficiency provides no benefit while adding risk.

Laboratory and animal studies describe hepcidin regulation, intestinal transport and iron-driven oxidative stress in tissues when iron is in excess.

Evidence gap: Non-human evidence. It informs dosing science and the rationale for caution with excess iron; it does not establish clinical benefits on its own.

Iron absorption is reduced by tea, coffee, calcium, high-dose zinc, some antacids and several medicines, and increased by vitamin C. It also reduces the absorption of some antibiotics and thyroid medicine, so timing separation matters.

Accidental overdose is a leading cause of poisoning deaths in young children — keep products in child-resistant containers and out of reach, and seek emergency help immediately after a suspected ingestion. In adults, unnecessary iron can accumulate, and people with haemochromatosis or repeated transfusions must not supplement without specialist input. Need should be confirmed by testing, because treating undiagnosed anaemia can delay finding a serious cause such as gastrointestinal bleeding or coeliac disease.

Tablets, liquids and intravenous preparations are all used clinically. Liquids stain teeth; intravenous iron is reserved for defined clinical situations.

Supplementation is for correcting documented deficiency and for defined higher-need situations such as pregnancy. Related approaches include identifying and treating the cause of blood loss, dietary iron with vitamin C-containing foods, and in some cases intravenous iron. Iron does not treat fatigue that is not caused by iron deficiency.

Educational example: an adult buys iron gummies for tiredness, feels no better after three months, and later turns out to have a bleeding source that testing would have found. The decision factors are whether iron studies were done, whether a cause was investigated, and whether the product was stored safely away from children. Questions for a clinician or pharmacist: do my results show deficiency, what is causing it, and how should I space iron from my other medicines? Iron marketed as an energy product to people with normal stores is a clear example of marketing outrunning evidence.