All supplements

Health · Evidence Strong

Iron (Bisglycinate)

A gentle iron form — only supplement if a blood test confirms deficiency.

Dosage

Only as directed by a physician after a serum ferritin test

Timing

Away from coffee, tea, calcium, and dairy

Evidence

Strong

Overview

Iron is one of the few supplements that should never be self-prescribed. Get a ferritin test first. If you are deficient, bisglycinate is generally better tolerated than ferrous sulfate.

Benefits

  • Corrects diagnosed iron deficiency
  • Supports oxygen transport when levels are low

Best for

Correcting diagnosed iron deficiency

Stacks with

Side effects

  • Constipation
  • Nausea
  • Dark stools

Warnings & cautions

  • Do not supplement iron unless a blood test confirms deficiency.
  • Iron overload is dangerous — hemochromatosis and other conditions require caution.
  • Keep away from children — iron overdose is a leading cause of pediatric poisoning.
  • Discuss with a physician if pregnant or breastfeeding.

Drug & condition interactions

  • Reduces absorption of certain antibiotics, thyroid medication, and levodopa — separate dosing.

Evidence notes

Iron corrects deficiency and iron-deficiency anemia. Supplementing without deficiency can cause harm.

Research references

  • [1] Camaschella C. Iron-deficiency anemia. N Engl J Med, 2015; 372:1832–1843

Medical disclaimer

This page is for general educational purposes only and is not medical advice. Individual response to supplements varies. Consult a licensed healthcare provider before starting any supplement — especially if you are pregnant, breastfeeding, under 18, taking prescription medication, or managing a medical condition.

Related supplements