Is Low Magnesium The Cause of Your Fatigue?

Fatigue is one of those symptoms that’s so prevalent in modern life that it can be hard to even realize it’s there. A lot of us feel tired—a lot of the time. In the U.S., 13.5 percent of adults report feeling “very tired” or “exhausted” most days or every day in the previous three months. From putting in too many hours at work to staying up too late to binge your favorite show, all sorts of culprits can underlie feelings of fatigue. One you might be overlooking, though, is low magnesium. Just like many of us are tired, many of us—an estimated 45 percent of Americans—are deficient in this important mineral.

It’s always best to check with your doctor to find out whether low mag could be giving you low energy, but it never hurts to watch for signals yourself, too. Here’s a look at the connection between magnesium and fatigue and the symptoms to keep an eye on.

• ABOUT OUR EXPERTS: Erin Jowett, M.S., R.D., L.D.N., is a registered dietitian and the owner of Integrative Weight and Wellness. Amanda Crowe, M.S., R.D., I.N.H.C., is a registered dietitian and the founder of Drive By Nutrition.

Why Low Magnesium Makes You Tired

Magnesium is a micronutrient. In other words, our bodies don’t require all that much of it (compared to macronutrients—fat, protein, and carbohydrates) to function well. But the smaller our needs, the more of an impact little deficiencies can make on physical symptoms.

One reason dropping magnesium levels might leave you fatigued is that magnesium is essential for energy production. “It plays a key role in making and stabilizing ATP, which is essentially your body’s energy currency—the fuel your cells actually run on,” explains registered dietitian Erin Jowett, M.S., R.D., L.D.N., owner of Integrative Weight and Wellness. “So when magnesium levels are low, it’s not that you’re lazy or unmotivated. Your body literally has a harder time producing and using energy efficiently, which can leave you feeling physically drained, mentally foggy, or just not like yourself.”

Read More: Your Guide to All of the Magnesium Supplements Out There

Magnesium doesn’t just play a role in ATP production, either. It also helps regulate the nervous system and allows muscles to relax. “When levels dip, muscle tension and nervous system stress can creep up, making your body feel like it’s working harder than it should. That constant, low-grade strain in the background can absolutely show up as fatigue,” Jowett says.

How to Tell If Low Energy Is From Low Magnesium

Wouldn’t it be nice if your body had a little magnesium sensor you could check to see if you’re running low? Alas, there’s no such clear sign—and fatigue has many potential causes.

Read More: Should You Be Taking a Magnesium Complex?

If you’re wondering whether low magnesium is the main culprit for your sluggishness, your doctor is the best detective to uncover the answers. They can run bloodwork (and potentially other medical tests) to check your levels. Since most magnesium is stored in tissues, a simple blood test doesn’t always reflect your body’s total status, explains registered dietitian Amanda Crowe, M.S., R.D., I.N.H.C., founder of Drive By Nutrition. That’s why a hair test called Hair Tissue Mineral Analysis (HTMA) could provide better insight, Jowett adds.

Other details from your medical history, such as your dietary habits, can fill in a clearer picture of your magnesium intake. Your doc will also likely evaluate other possible underlying causes of fatigue, like iron levels, thyroid health, blood sugar balance, stress, and basic sleep habits.

Then again, even before you get to the exam room, some accompanying symptoms could be clues that low magnesium is causing your can’t-pull-myself-off-the-couch malaise. “Other signs may include muscle cramps, eye twitching, headaches, irritability, and poor sleep,” says Crowe. Chronic constipation and heightened feelings of anxiety are additional telltale indicators of mag deficiency.

Jowett also often sees another classic low-magnesium pattern. “I call it ‘tired but wired,’” she says. “You’re physically exhausted, but you can’t fully relax.” When patients report having trouble falling asleep, feeling like their mind won’t quiet down, or waking up feeling like they didn’t really rest, she starts thinking magnesium is part of the picture. “Since magnesium plays a big role in calming the nervous system and helping muscles relax, low levels can make it harder for your body to shift into recovery mode,” she explains.

How to Get Your Magnesium Intake Back on Track

Thankfully, many people can bump magnesium levels back into the black with simple diet changes. A food-first approach involves plenty of delicious choices! 

“Magnesium-rich foods include pumpkin seeds, almonds, spinach, black beans, lentils, whole grains, and dark chocolate,” says Crowe. Putting these foods on your plate not only provides magnesium, but can also boost your intake of other energy-enhancing nutrients like carbohydrates, B vitamins, and zinc.

Read More: 6 Magnesium-Packed Foods You Need to Try

The key, of course, is actually eating these foods regularly. “Throwing spinach into one smoothie a week isn’t going to move the needle,” Jowett cautions. “It has to be part of your normal rotation for it to really make a difference.” 

Adult men need about 420 milligrams of magnesium daily, while adult women need 320 milligrams. For reference, one cup of fresh spinach contains 23 milligrams, while one ounce of almonds contains 77 milligrams, and one cup of black beans contains 332 milligrams. If you’re not sure where to begin, a registered dietitian can help you craft a meal plan that refills your magnesium tank.

If food alone isn’t doing the trick to get you “magnes-ified” (and get your energy levels where you want them), it may be time for a supplement. For fatigue, both Jowett and Crowe recommend magnesium glycinate or magnesium malate. “Glycinate is great if you’re also dealing with stress or sleep issues because it’s gentle and calming,” says Jowett. Meanwhile, “malate can be helpful if your fatigue feels more muscle-related or like low, dragging energy, since it supports cellular energy production.” For healthy adults, a daily supplement dosage of 250 to 500 milligrams is considered safe.

Other forms—like magnesium oxide or citrate—aren’t the best choices if energy is your goal. “They’re not absorbed as well and tend to act more like laxatives instead of rebuilding your magnesium levels,” Jowett says. 

And while topical magnesium sprays and lotions are available, dietary supplements are more evidence-based. “Research on absorption through the skin is still limited compared to oral supplementation,” Crowe says. That’s not to say these options can’t help, but it’s still a good idea to consider an oral supplement your first line of attack.

Of course, you can certainly try incorporating high-magnesium foods and taking a supplement. Just watch out for signs of overdoing it. Though rare, a magnesium overload can look like a headache, nausea, or muscle weakness. If low magnesium is giving you the low-energy blues, a combo of diet and supplementation could get you back to that calm-yet-wakeful state you’re seeking.