What can magnesium do for you and how much do you need?

In the world of nutrients, minerals, vitamins, and supplements, magnesium seems to be having a moment. Perhaps it’s long overdue: in many ways, magnesium has been overlooked, underappreciated, or even forgotten. That may be ending.

But why is magnesium getting so much attention lately? Are claims about its benefits true? Are you getting enough magnesium, or should you join the rising number of people who take magnesium supplements every day? If you have these questions, this post is for you.

What is magnesium?

Magnesium is a mineral the human body needs to function properly. It’s especially important for a healthy cardiovascular system, nerves, muscles, and bones. It helps regulate the body’s calcium and blood sugar levels, and it’s vital for the body’s production of protein. And that’s just the short list: more than 300 chemical reactions in the body rely, at least in part, on magnesium.

Are you getting enough magnesium?

Most of us don’t need to fret over how much magnesium we’re getting. The recommended daily amount of magnesium — 320 milligrams (mg) a day for women and 420 mg a day for men — isn’t difficult to take in through a healthy diet.

But getting extra magnesium is important for people with magnesium deficiency, and those who have complications of pregnancy known as preeclampsia and eclampsia.

More limited evidence suggests that extra magnesium could also be helpful for people with:

• cardiovascular disease, including high blood pressure or coronary artery disease
• insomnia
• migraines
• anxiety
• diabetes and diabetic neuropathy
• muscle soreness after exercise
• constipation.

There are even studies suggesting that magnesium supplements might help with brain health and smoking cessation.

Many studies of the potential benefits of magnesium are quite small, and some have inconsistent results. Despite the shaky evidence for many claims, this large and expanding list of proposed health benefits is one reason magnesium supplements have been increasingly popular in recent years.

Is there a test to check magnesium levels?

A blood test can measure whether you’re getting enough magnesium. The normal range for blood magnesium is 1.7 to 2.2 milligrams per deciliter (mg/dL).

In general, the body does a great job of regulating the blood levels of magnesium. If levels rise, the kidney dumps excess magnesium into the urine; if levels fall, the kidneys hold onto more magnesium, bones release the mineral into the circulation, and the intestinal absorption of magnesium from the diet increases.

What are the symptoms of low magnesium?

The symptoms of too little magnesium (hypomagnesemia) include nausea, fatigue, and reduced appetite. Of course, these symptoms can be due to many other conditions, such as a stomach bug or medication side effects.

When severe, low magnesium may cause numbness in the arms and legs, muscle cramps, and an abnormal heart rhythm.

Some common causes of magnesium deficiency are:

• malnutrition (or simply choosing a diet that’s low in magnesium)
• gastrointestinal conditions (such as Crohn’s disease) that cause vomiting, diarrhea, or poor absorption of magnesium
• kidney disease, some types of which cause excess loss of magnesium in the urine
• medications like diuretics or certain types of chemotherapy
• alcohol use disorder, because alcohol can boost the loss of magnesium in the urine.

Studies also suggest that magnesium deficiency is common among adults over age 70. The reasons include low intake of magnesium, poor absorption in the digestive tract, use of certain medicines, and kidney disease.

What are the symptoms of too much magnesium?

The symptoms of too much magnesium (hypermagnesemia) include nausea, headache, muscle weakness, and trouble breathing.

Hypermagnesemia is quite rare. Most people with higher-than-normal blood levels of magnesium have kidney failure. Others may be taking too much magnesium in supplements or taking certain medicines (such as magnesium-containing laxatives).

Which foods are good sources of magnesium?

Magnesium-rich foods like green, leafy vegetables (such as spinach), beans, nuts, and whole grains will help you get there. Pumpkin seeds, soy milk, bananas, and dark chocolate (in moderation!) are also good sources.

Eating one serving of spinach, an ounce of almonds, and a banana provides 190 mg of magnesium. That’s nearly 60% of the daily recommendation for women and 45% for men. Fortunately, magnesium is found in many healthy foods, so a good diet (such as the Mediterranean diet) will usually provide all the magnesium that you need.

Should you take a magnesium supplement?

Unless you have a diagnosed or suspected magnesium deficiency, or a condition with clear evidence of benefit such as preeclampsia or Crohn’s disease, there’s no compelling reason to routinely take a magnesium supplement.

For some conditions, such as insomnia or migraine headaches, a magnesium supplement may be worth a try. But it’s a good idea to run this by your doctor first. All supplements come with a risk of side effects. In the case of magnesium, this includes nausea and diarrhea. Magnesium supplements can also interact with other medicines and supplements you’re taking.

Which type of magnesium is best?

Magnesium found in foods is usually the best choice. When needed, magnesium supplements are available in several different forms, including:

• magnesium citrate, which is often taken as a laxative for gut health
• magnesium glycinate, which is commonly promoted for improved sleep and reduced anxiety
• magnesium oxide, which tends to be taken for constipation or indigestion.

All of these can provide extra magnesium. So the choice mostly comes down the reason you’re taking it, whether you experience side effects, cost, and personal preference.

Daily supplements of less than 350 mg usually are considered safe. But when people have certain health conditions such as kidney disease, it can be tricky to get the right amount of magnesium, and monitoring blood levels is important.

It’s safest to check with your doctor if you’re wondering whether to start taking a magnesium supplement, or unsure which one or how much to take.

The bottom line

Most people are fine without paying too much attention to their magnesium status. If you have concerns about whether you’re getting enough magnesium and whether you should take a supplement, ask your doctor about it. But don’t be surprised if you get some familiar advice: Choose a healthy, well-balanced diet. Your body will take care of the rest.