High-dose magnesium supplements may reduce iron absorption when taken together.
Magnesium and iron can compete for absorption in the gastrointestinal tract at higher supplemental doses.
Separate magnesium and iron supplements by 2 hours for best absorption of both.
Take magnesium and iron supplements at different times of day for best absorption.
Both minerals compete for absorption. Iron is best absorbed on an empty stomach in the morning; magnesium is often better tolerated in the evening.
Take iron in the morning with vitamin C. Take magnesium in the evening or at a different meal.
Known drug category interactions for these supplements. Especially relevant if you take prescription medications.
Magnesium binds to these antibiotics in the gut, significantly reducing their absorption and effectiveness.
Take magnesium at least 2 hours before or 4-6 hours after these antibiotics.
Iron reduces levothyroxine absorption.
Take levothyroxine at least 4 hours before or after iron supplements.
Reference values for safe daily intake of these supplements.
UL is for supplemental magnesium only (not dietary). Diarrhea is the primary adverse effect.
GI distress above UL. Risk of iron overload in people with hemochromatosis.