Can I take Folic acid and Magnesium together?
Drug interaction guide
Originally published 25 Jan 2026
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There is no known harmful interaction between folic acid and magnesium. In fact, they are often taken together in multivitamins or during pregnancy.
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Why this happens
Folic acid (a B vitamin) and magnesium (a mineral) are absorbed and processed by the body through different pathways. They do not interfere with each other's effectiveness or increase the risk of side effects.
What you should do
You can safely take folic acid and magnesium at the same time. No special precautions are needed.
Important precautions
Vitamin B12 deficiency (Pernicious Anaemia)
Folic acid can mask the symptoms of vitamin B12 deficiency. If you have B12 deficiency, taking folic acid alone can allow serious nerve damage to progress even though your blood count appears normal. Your doctor must ensure your B12 levels are checked before or during treatment.
Severe kidney disease (renal impairment)
If your kidneys are not working properly, magnesium can build up to toxic levels in your blood, which can lead to serious heart and breathing problems. Do not take magnesium supplements unless specifically monitored by your doctor.
Food and drink warnings
Alcohol
It is best to avoid or strictly limit alcohol while taking folic acid. Alcohol interferes with the way your body absorbs and uses folic acid, which can make the treatment less effective. Chronic alcohol consumption is a common cause of folate deficiency.
It is best to avoid or strictly limit alcohol while taking magnesium supplements. Alcohol increases the amount of magnesium your body gets rid of through urine, which can make the supplement less effective. Additionally, both alcohol and high doses of magnesium can have a laxative effect, increasing the risk of stomach upset.
Dairy products
Dairy products are high in calcium. Large amounts of calcium can interfere with how your body absorbs magnesium. If you are taking a high-dose magnesium supplement, try to take it at least 2 hours apart from eating large amounts of dairy or taking calcium supplements.
Caffeine (Coffee and Tea)
Caffeine can have a mild diuretic effect, which may increase the loss of magnesium through your urine. If you consume high amounts of caffeine, it may reduce the effectiveness of your supplement.
Using other medicines
Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.
Disclaimer
This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.
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Article history
The information on this page is written and peer reviewed by qualified clinicians.
Article also available in English, German, Spanish, French, Italian, Portuguese, Hindi, Hebrew, Arabic, and Swedish.
25 Jan 2026 | Originally published
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