We asked a doctor if it’s safe to take magnesium without a deficiency

Magnesium is growing in popularity, especially if you have trouble falling asleep at night. But before you start taking this supplement before bed, we asked our chief medical officer, Sohaib Imtiaz, MD, if there were any risks to taking magnesium.

Q: If I eat a fairly balanced diet and don’t have a magnesium deficiency, is it still safe to take a magnesium supplement to help me sleep?

Imtiaz: Taking magnesium can be harmful if you don’t suffer from it. The most common side effect is diarrhea, especially due to poorly absorbed magnesium, such as magnesium oxide.

Some studies suggest that doses above 350 milligrams per day, which is the current tolerable limit, are suitable for most people, but in a few cases they can cause significant side effects.

Excess magnesium can cause a condition called hypermagnesemia, a condition more common in people with kidney problems or kidney failure. People with a mild case of hypermagnesemia may not have any symptoms, but moderate or severe cases may cause confusion and drowsiness.

How to know if you have a magnesium deficiency

Magnesium status can be difficult to assess because serum levels do not reflect the body’s stores. A blood test may show low levels of magnesium, but it does not indicate how much your body stores.

You might have normal blood magnesium levels, but you don’t know your storage, so it’s difficult to assess.

If so, you can probably take a magnesium supplement, but retest to make sure the blood level isn’t too high. Getting regular blood tests can ensure you stay at normal levels.

When to stop taking magnesium

If you start to experience symptoms such as dizziness and confusion, these could be signs of hypermagnesemia. You should stop taking it if you feel nauseous or generally not feeling well.

The biggest problem with taking magnesium is potential kidney problems. It may also interact with certain medications, so always ask your doctor.

The most common risk of taking magnesium if you are not deficient is having diarrhea. That’s kind of the big problem.