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Do You Need to Supplement Magnesium?

Whether you need to supplement magnesium depends on a few factors.

Check Your Diet First

Do you already get enough magnesium through your diet?

Tally up what you normally eat in a day and see whether it meets the daily requirement for magnesium.

The recommended daily amount of magnesium is 420mg a day for men and 320mg a day for women.

What foods do you normally eat every day?

Find out how much magnesium is in each of them and then tally them up to see whether it meets this daily requirement.

If it doesn't, then you may need to supplement.

Fortunately, magnesium is present in many of the foods that we eat. So whether you eat a varied diet, a vegetarian diet, a vegan diet, a standard american diet, you can still obtain enough magnesium regardless.

One medium-sized banana contains about 32mg of magnesium. So if you eat a few a day, that may already bring you to half of your magnesium requirement daily.

One papaya, depending on the size, provides about 30-50mg of magnesium. A small papaya provides about 30mg, while a large papaya may provide arond 50mg of magnesium.

Dates are rich in magnesium, with a single date providing about 13-15mg of magnesium. A few dates can add up.

Medium-sized tomatoes provide about 13-14mg of magnesium. Cucumbers providing near the same.

Thus, through a healthy diet, it isn't very hard to meet your daily magnesium requirements.

Get Tested To See Your Magnesium Status

However, even with a healthy diet, if you have any doubts that your daily intake may be inadequate, then you can get tested to see your magnesium status.

The most unreliable test for magnesium is to check your serum magnesium levels because your body always keeps this level in a tight range of 1.7 to 2.2mg/dL.

Serum magnesium tests are considered unreliable for assessing total body magnesium because less than 1% of the body's magnesium is stored in the blood. Over 99% of magnesium is stored in the bones, muscles, and soft tissue. The body keeps the magnesium level in the blood within its tight range to assure appropriate cardiac function. To do this, it will pull magnesium from bone reserves to keep the blood levels stable.

This is why checking just the serum magnesium level doesn't tell the real picture in the body.

To get an accurate level of the body's magnesium status, a red blood cell (RBC) magnesium test should be done. This test measures the magnesium levels inside red blood cells, which is generally considered more reflective of tissue stores.

A whole blood magnesium test can also be done, which checks the magnesium levels in both serum and red blood cells.

However, a red blood cell test is more likely sufficient enough, as serum levels are usually tightly regulated within the narrow range.

So what result is optimal for the red blood cell magnesium test?

Lab range for normal values from 4.0-6.8mg/dL or 3.6-7.5mg/dL.

Optimal ranges are generally considered from 6.0-6.5mg/dL, on the higher end of the normal range.

So if you have a magnesium in this range, then you have adequate reserves and you can continue what you have been doing without any need to supplement (assuming you aren't currently doing so).

If your levels are low, you can either choose to increase it naturally by incorporating more high-magnesium foods in your diet or you can go ahead and supplement if you don't want to make any adjustments to your diet.

Be aware, though, that you want to meet the daily requirements more or less.

Don't Take More Magnesium Than What Is Necessary

Taking more is not going to be of benefit. The body will excrete excess magnesium usually in the form of diarrhea. This is why products such as Milk of Magnesia are used as laxatives. This can be the unintended effect by taking too much magnesium.

Therefore, getting enough is the goal, not getting in as much as you can, which only will lead to symptoms such as having a laxative effect.

So you can seek to supplement magnesium but before doing that, evaluate your diet to see if you are meeting the daily requirements. If possible, do an RBC magnesium test to check your status. You can have a magnesium consultation with us, where you will be tested for your Magnesium, RBC level and given guidance by a provider. If you are deficient, and you are unwilling or unable to modify your diet, supplementation can then be a smart strategy you can use.

By David Hylton, FNP-C

February 21, 2026