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Can I take Magnesium and Vitamin C together?

Drug interaction guide

There is no harmful interaction between magnesium and vitamin C. In fact, taking them together is generally considered safe and may even be slightly beneficial for absorption.

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Why this happens

Vitamin C creates a more acidic environment in the stomach, which can help the body dissolve and absorb certain forms of magnesium more effectively. They do not interfere with each other's metabolism or excretion.

You can safely take these two supplements together. However, be aware that high doses of either magnesium or vitamin C can cause diarrhoea or stomach upset. If you experience these symptoms, try taking them at different times of the day or reducing the dose.

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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.

Kidney stones (renal calculi)

High doses of vitamin C can increase the amount of oxalate in your urine, which significantly raises the risk of developing kidney stones, especially if you have had them before.

G6PD deficiency

Very high doses of vitamin C can cause oxidative stress and lead to the breakdown of red blood cells (haemolysis) in individuals with G6PD deficiency.

Haemochromatosis

High doses of vitamin C can significantly increase the amount of iron your body absorbs from food. If you have haemochromatosis, this can lead to dangerous levels of iron buildup, which may damage your heart and liver. Avoid vitamin C supplements unless specifically directed by your specialist.

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.

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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