Research shows that ferrous iron supplements are better absorbed than ferric iron. The most common forms include:
- Ferrous sulfate: Most common, 20% elemental iron
- Ferrous gluconate: Gentler on stomach, 12% elemental iron
- Ferrous bisglycinate: Highest absorption rate, fewer side effects
Ferrous bisglycinate shows superior absorption and fewer gastrointestinal side effects compared to other forms. Liquid iron supplements may also be better absorbed than tablets, especially for people with digestive issues or after gastric surgery.
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Last Updated: October 27, 2025
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