Iron Supplements: Benefits, Dosage and Safety
Iron supplements treat iron deficiency and iron-deficiency anemia, which are common in people with heavy periods, pregnancy, frequent blood donation or vegetarian diets. Only take iron if a blood test shows you need it: excess iron is harmful, and iron overdose is dangerous for children.
Evidence at a glance
| Use | Grade | What the research shows |
|---|---|---|
| Treating iron-deficiency anemia | A | Oral iron reliably restores hemoglobin and iron stores. |
| Fatigue without deficiency | D | No benefit if iron levels are normal. |
A: strong, consistent human evidence · B: moderate · C: limited or mixed · D: good evidence of no benefit.
Iron carries oxygen in red blood cells. Low iron causes tiredness, shortness of breath, pale skin, hair shedding and restless legs.
How to take it
Take iron with a source of vitamin C and at least 2 hours apart from calcium, tea, coffee and antacids. Some people tolerate alternate-day dosing better. Gentler forms such as bisglycinate cause fewer stomach problems; see ferrous bisglycinate vs ferrous sulfate.
Safety and interactions
Constipation, nausea and dark stools are common. Iron reduces absorption of levothyroxine and some antibiotics. People with hemochromatosis must avoid iron supplements. Keep iron out of reach of children.
Always tell your doctor and pharmacist about the supplements you take. Check combinations with our interaction checker.
Sources
This page is for education and is not a substitute for advice from your doctor. Read our medical disclaimer.