Studies indicate that ferrous iron supplements are generally better absorbed than ferric iron. The most common forms ranked by bioavailability are:
- Ferrous bisglycinate (most bioavailable)
- Ferrous sulfate
- Ferrous gluconate
- Ferrous fumarate
Iron bisglycinate shows superior absorption and fewer gastrointestinal side effects. However, individual responses vary. Liquid forms may be better absorbed than tablets, particularly for those with digestive issues. The addition of vitamin C can significantly enhance absorption regardless of the form chosen.
✓ Expert Reviewed: This content has been reviewed by qualified professionals in the field.
Last Updated: September 18, 2025
Disclaimer: This information is for educational purposes only and should not replace professional medical advice. Always consult with a healthcare provider before making health decisions.
Editorial Standards: Our Medical Content StandardsThe Health Research Team is a collaborative network of healthcare professionals, graduate researchers, and medical science students dedicated to synthesizing peer-reviewed health research for public education. Our interdisciplinary approach combines expertise from nutrition science, physiotherapy, nursing, and medical research to provide comprehensive, evidence-based health information.Click to read our Editorial Policy in details - Medical Oversight: All health information is overseen by board-certified physicians and follows FDA guidelines for health content