Ascorbic acid × Iron oral (salts: sulfate, bisglycinate, fumarate, gluconate, polymaltose; heme iron polypeptide, lactoferrin)
MinorVitamins. Antioxidants×Oral iron preparations; antianaemic agents
Updated · Methodology
Mechanism
This pair does not subtract, it adds. Ascorbic acid reduces ferric iron to ferrous, the form the enterocyte absorbs, and counteracts the phytates and polyphenols that bind it. It is the only combination on this list that is sought deliberately.
Symptoms
No adverse effects of its own. At very high vitamin C doses alongside iron some people notice more stomach upset, which settles on a lower dose.
Management
Use it: iron with a glass of orange juice, or with vitamin C built into the tablet, performs better than iron alone. What does help is keeping it away from tea, coffee and dairy, which pull the other way. In haemochromatosis or iron overload this boost stops being desirable.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
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Sources
- NIH Office of Dietary Supplements: Iron – Health Professional Fact Sheet (2025)– NIH ODS, Iron, Interactions with Medications