Vitamin C significantly enhances non-heme iron absorption.
Ascorbic acid reduces ferric iron to ferrous iron, the more absorbable form, and chelates iron to keep it soluble.
Take vitamin C with iron supplements or iron-rich meals to improve absorption. Even 100mg of vitamin C can double iron absorption.
Known drug category interactions for these supplements. Especially relevant if you take prescription medications.
Iron reduces levothyroxine absorption.
Take levothyroxine at least 4 hours before or after iron supplements.
Reference values for safe daily intake of these supplements.
High doses may cause diarrhea and GI distress.
GI distress above UL. Risk of iron overload in people with hemochromatosis.