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Can I take Magnesium and Vitamin B12 together?

Drug interaction guide

There is no known harmful interaction between magnesium and vitamin B12. In fact, these two nutrients often work together in the body to support energy production and the nervous system.

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Why this happens

Magnesium and vitamin B12 use different pathways for absorption in the digestive tract and do not interfere with how the body processes or eliminates each other.

It is safe to take magnesium and vitamin B12 together. You can take them at the same time of day, with or without food, unless your doctor or the product packaging suggests otherwise.

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Kidney disease

If you have severe kidney problems, your body may not be able to remove excess magnesium, leading to dangerously high levels in the blood. Check with your doctor before use.

Alcohol

It is best to avoid or strictly limit alcohol when taking magnesium. Alcohol acts as a diuretic, which can increase the amount of magnesium your body loses through urine, potentially making the supplement less effective. Additionally, chronic alcohol use can lead to magnesium deficiency.

It is best to avoid or strictly limit alcohol while taking Vitamin B12. Heavy alcohol consumption can interfere with the body's ability to absorb Vitamin B12 from the gut and can reduce the amount of the vitamin stored in the liver.

Dairy products (Milk, Cheese, Yoghurt)

Avoid taking magnesium supplements at the same time as large amounts of dairy products. Dairy is high in calcium, and high doses of calcium can compete with magnesium for absorption in the gut, meaning you may not get the full benefit of your supplement. It is best to space them at least 2 hours apart.

Caffeine (Coffee, Tea, Energy drinks)

It is best to limit caffeine intake around the time you take magnesium. Like alcohol, caffeine has a mild diuretic effect and can increase the excretion of magnesium through the kidneys.

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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.

  • 25 Jan 2026 | Originally published
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