Does Iron Bisglycinate interact with Calcium?

Written to our editorial standards · reviewed against published research· Updated 2 Jun 2026
Space them apart· strong evidence

Calcium blocks iron absorption by up to ~50%.

Calcium competes with non-heme iron for the same DMT1 uptake transporter in the gut, so dairy or a calcium supplement in the same sitting can cut iron absorption by roughly a third to a half. The effect is largest for supplemental and plant iron and smaller for heme iron from meat.

What to do

Take iron on an empty stomach with about 200 mg of vitamin C, and keep calcium-rich meals or calcium pills at least 2 hours away. If iron upsets your stomach, a gentle form like bisglycinate with a small low-calcium snack is a reasonable compromise.

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Iron Bisglycinate
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Common questions

Can I take Iron Bisglycinate and Calcium together?
Space them apart. Take iron on an empty stomach with about 200 mg of vitamin C, and keep calcium-rich meals or calcium pills at least 2 hours away. If iron upsets your stomach, a gentle form like bisglycinate with a small low-calcium snack is a reasonable compromise.
Why do Iron Bisglycinate and Calcium interact?
Calcium competes with non-heme iron for the same DMT1 uptake transporter in the gut, so dairy or a calcium supplement in the same sitting can cut iron absorption by roughly a third to a half. The effect is largest for supplemental and plant iron and smaller for heme iron from meat.

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Educational use only, not medical advice. Interaction risk depends on dose, your health, and any medications. Always consult a qualified clinician, especially if you take prescription drugs or are pregnant or nursing.