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Can I take Magnesium and Simvastatin together?

Drug interaction guide

Taking magnesium supplements at the same time as simvastatin can lower the amount of the medicine your body absorbs. This means the simvastatin may not work as well to lower your cholesterol.

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Why this happens

Magnesium (often found in antacids or supplements) can bind to simvastatin in the digestive tract or change the acidity of the stomach, which reduces the amount of the drug that enters your bloodstream.

You do not need to stop taking either, but you should separate the doses. Take your simvastatin at least 2 hours before or 2 hours after taking any magnesium supplement or magnesium-containing antacid.

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Pregnancy

Do not take simvastatin if you are pregnant, planning to become pregnant, or breastfeeding. Simvastatin can cause serious harm to an unborn baby. Stop taking it immediately and contact your doctor if you think you are pregnant.

Muscle problems (Myopathy/Rhabdomyolysis) - simvastatin

Contact your doctor immediately if you experience unexplained muscle pain, tenderness, or weakness. This risk is significantly increased if you drink large amounts of grapefruit juice or take certain other medicines.

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 while taking these medicines. For simvastatin, regular heavy drinking increases the risk of liver problems and muscle damage. For magnesium, alcohol can increase the amount of magnesium your body loses through urine, making the supplement less effective.

Grapefruit juice

You must avoid drinking grapefruit juice or eating grapefruit while taking simvastatin. Grapefruit contains compounds that significantly increase the level of simvastatin in your blood, which greatly increases your risk of serious side effects, such as muscle damage (rhabdomyolysis).

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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