Magnesium: Benefits, Immune Support and How Much You Need

Magnesium is a mineral that's involved in more than 300 different processes in your body, from making energy to keeping your heartbeat steady [1]. It also works closely with vitamin D and calcium, which is why research-based micronutrient formulations include it as part of a team [2] [3].

What is magnesium?

Magnesium is a mineral your body needs every day. It's found naturally in many of the foods we eat, added to others, and yes, available as a supplement. You'll even find it in some antacids and laxatives [1].

An adult body holds about 25 grams of magnesium. Somewhere between half and 60% of it is stored in your bones, and most of the rest sits inside your soft tissues, such as your muscles. Less than 1% is in your blood [1]. Your kidneys keep the balance in check, holding on to more magnesium when your levels start to run low [1].

What does magnesium do for the body?

Magnesium's biggest job is helping your body's enzymes do their work. It acts as a helper, or cofactor, for more than 300 enzyme systems [1].

That's a lot of jobs for one mineral, so it helps to group them into five areas: energy, muscles and nerves, the heart, the bones, and the body's own antioxidant defenses. Let's take each one individually.

• Energy: Magnesium is required to turn the food you eat into energy your cells can use [1].
• Muscles and nerves: Magnesium helps move calcium and potassium in and out of your cells. That's how your nerves send signals and your muscles contract and relax [1].
• The heart: That same process helps keep a normal heart rhythm. Magnesium also plays a role in regulating blood pressure and blood sugar [1].
• The bones: Magnesium helps build bone, and it influences parathyroid hormone and the active form of vitamin D, two of the main regulators of bone health [1].
• Antioxidant defenses: And the last one. Your body needs magnesium to make glutathione, one of its own most important antioxidants. It's also needed to make DNA, RNA and proteins [1].

Why is magnesium important for the human body?

Because magnesium is involved in so many processes, running low over time can touch almost every system in the body. The early signs of a shortfall include loss of appetite, nausea, fatigue and weakness [1].

Low intake is more common than many people realize. About half of Americans, 48%, get less magnesium from food and drinks than they need [1]. Refined grains are part of the reason. Processing strips away the germ and bran, which is where much of the magnesium lives [1].

Magnesium also ties into the two processes research links to declining health with age: increased oxidative stress, which is damage from excess free radicals, and chronic inflammation [2]. A long-term magnesium shortfall is linked to more of both [4] [5]. That's one reason comprehensive micronutrient formulations include magnesium alongside antioxidants, B vitamins and other minerals [3] [6].

There's a teamwork angle, too. Your body needs magnesium to make, move and activate vitamin D [4]. Magnesium does its best work as part of the team, not by itself.

How does magnesium support immune function?

Magnesium supports immune function by helping your immune cells, especially T cells, do their jobs, and by helping keep inflammation in balance [4] [5]. When magnesium runs low, immune function can weaken, either for a short time or over the long term [5].

Think of your immune system as having two jobs: responding strongly when a threat shows up, and calming back down once the job is done. Let's look at how magnesium helps with each.

• First-line (innate) defense: This is your body's rapid-response team. Magnesium supports macrophages, the immune cells that engulf germs, and helps regulate your body's early response to infection [5].
• Targeted (adaptive) defense: This is the part of your immune system that learns and remembers specific threats. Your T cells need enough magnesium to recognize germs, respond to them and clear them out [5]. Magnesium also helps your body make antibodies, the proteins that tag specific invaders [4].
• Balanced inflammation: A long-term magnesium shortfall is linked to higher everyday levels of inflammation and oxidative stress. Getting enough magnesium helps keep the response in proportion [4] [5].

Magnesium also works hand in hand with vitamin D, another key immune nutrient, because your body needs magnesium to activate it [4].

Getting the most from magnesium

If you want to get the most out of magnesium, here are five things the research points to.

• Choose a well-absorbed form: Forms that dissolve well, such as magnesium citrate, chloride, aspartate and lactate, are absorbed better than magnesium oxide or sulfate [1]. Research-based micronutrient formulations use magnesium citrate [3] [6].
• Keep supplement amounts modest: The Micro Daily EMF formula provides 150 mg of magnesium (as magnesium citrate) a day, 36% of the Daily Value, split between a morning dose and an evening dose [9]. That's well under the 350 mg daily upper limit for magnesium from supplements, and it leaves plenty of room for the magnesium you get from food [1].
• Don't take it alone: Magnesium works as a team with calcium and vitamin D3. Research-based formulations combine all three with antioxidants and B vitamins, because single nutrients taken by themselves tend to give inconsistent results [2] [3].
• Take your formula twice a day: Comprehensive formulas are designed to be split into a morning dose and an evening dose, which helps keep nutrient levels in your body steadier throughout the day [7] [8].
• Eat your greens, beans, nuts and seeds: Food is still your foundation. Supplements are there to help fill the gaps [1].

One last thing to keep in mind: very high doses of zinc from supplements, around 142 mg a day, can interfere with how well you absorb magnesium [1]. It's one more reason balanced formulas matter.

Frequently asked questions about magnesium

How much magnesium do I need each day?

Most adult men need 400 to 420 mg a day, and most adult women need 310 to 320 mg. During pregnancy, the amount rises to 350 to 400 mg. Children need 80 to 240 mg, depending on age [1]. For adults, the upper limit for magnesium from supplements is 350 mg a day. That limit doesn't include the magnesium in your food [1].

What foods are high in magnesium?

Nuts, seeds, beans and leafy greens are your best sources. One ounce of roasted pumpkin seeds has about 156 mg, chia seeds about 111 mg, and almonds about 80 mg. Half a cup of boiled spinach has about 78 mg, and half a cup of cooked black beans about 60 mg [1].

Who is most likely to be low in magnesium?

The groups most at risk are older adults, people with type 2 diabetes, people with alcohol dependence, and people with digestive conditions such as Crohn's or celiac disease. Men over 71 and teenagers are the most likely to get too little from their diet [1].

What are the signs of low magnesium?

Early signs include loss of appetite, nausea, vomiting, fatigue and weakness. If it gets worse, people can have numbness, tingling, muscle cramps and an abnormal heart rhythm [1]. Severe deficiency is uncommon in healthy people, because the kidneys hold on to magnesium when levels drop [1].

Can you take too much magnesium?

Not from food, because healthy kidneys flush out the extra. But high doses from supplements or medicines can cause diarrhea, nausea and stomach cramps. Very large doses, usually from laxatives or antacids, can be dangerous, especially for people with kidney problems [1].

Does magnesium interact with medications?

Yes. Magnesium can reduce how well you absorb some antibiotics and osteoporosis drugs, so they're usually taken a few hours apart. Some diuretics and long-term use of heartburn drugs called proton pump inhibitors can lower your magnesium levels [1]. If you take any of these, talk with your healthcare provider.

Explore more micronutrients

Magnesium works alongside other nutrients. Learn more about vitamin D, iron, vitamin B12, calcium, zinc, potassium and folate.

Key sources: NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals [1]; Ashique S, et al., "A narrative review on the role of magnesium in immune regulation, inflammation, infectious diseases, and cancer," Journal of Health, Population and Nutrition, 2023 [5]; Prasad KN, Micronutrients in Health and Disease, CRC Press, 2019 [2]. Every numbered citation links to its full entry on our References page.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Talk with your healthcare provider before starting any supplement, especially if you are pregnant, nursing, taking medication or have a medical condition.