Can Low Magnesium Make You Tired? Yes, Here’s How to Fix It

When you feel tired, everything in life feels harder. But finding out what’s causing your tiredness isn’t straightforward. 

Low magnesium can make you tired — and it is common — but there are many other causes of tiredness, and you could have more than one at the same time. 

Below, we dive more into how low magnesium can make you tired, the symptoms of magnesium deficiency, and how the RISE app can boost your energy levels — whether low magnesium is to blame or not.

Advice From a Sleep Doctor

“One symptom of low magnesium levels is fatigue," says Dr. Chester Wu. "That’s because magnesium plays a critical role in energy production. Low magnesium is also linked to sleep problems, which could also make you feel tired. Speak to your healthcare provider to get tested for a magnesium deficiency and prioritize sleep as much as you can to boost your energy levels.”

Dr. Chester Wu is double board certified in Psychiatry and Sleep Medicine, and provides sleep medicine services, medication management, and psychotherapy to adults at his private sleep medicine and psychiatry practice.

Can Low Magnesium Make You Tired? 

Yes, low magnesium can make you tired. When you’re not getting enough of the nutrient, many processes in your body are thrown off, which could cause tiredness, weakness, or health issues.

Why does low magnesium cause tiredness?

• Magnesium is essential for energy production: Magnesium's critical role in ATP production means it directly impacts how energy is stored and used in cells. Low magnesium can disrupt this process, leading to lower energy levels and increased fatigue.
• Magnesium regulates muscle and nerve function and electrolyte balance: Magnesium is important for proper nerve transmission and muscle contraction, and it also assists in the transport of other vital electrolytes, such as calcium and potassium, into cells. These electrolytes are essential for maintaining healthy muscle and nerve functions. Their imbalance due to low magnesium can lead to fatigue, muscle cramps, decreased physical performance, and brain fog.
• Magnesium is critical in antioxidant defense and reducing oxidative stress: Magnesium deficiency is linked to lower antioxidant capacity and increased oxidative stress. Oxidative stress can affect energy metabolism and contribute to cellular damage and fatigue.
• Magnesium regulates glucose and blood pressure levels: Magnesium helps to regulate blood sugar levels and blood pressure, both of which are crucial for overall metabolic health. Fluctuations in glucose and blood pressure can lead to energy dips and fatigue.
• Magnesium supports protein synthesis: Magnesium plays a role in protein synthesis, the process of building new proteins that are essential for cell function and repair. A deficiency can slow down this process, leading to reduced cellular function and recovery, contributing to fatigue.
• Magnesium supports healthy sleep patterns: Magnesium helps regulate neurotransmitters that affect sleep. Low magnesium is linked to sleep disorders, like restless leg syndrome and insomnia, as well as mental health issues like depression and anxiety, all of which can disrupt sleep and contribute to tiredness. Those who have a higher magnesium intake from food and supplements are more likely to get enough sleep. And higher dietary intake of magnesium is linked to decreased odds of falling asleep during the day in women. 

Heads-up: Confusingly, low magnesium (hypomagnesemia) and a magnesium deficiency are related but distinct: Hypomagnesemia is a specific, measurable low magnesium level in the blood. Magnesium deficiency refers to a broader systemic shortfall that may not be detectable through blood tests alone, making it more difficult to diagnose. 

You can have low blood magnesium levels without a broader deficiency, and vice versa.

Fortunately, for our purposes in understanding how low magnesium can make you tired, they have broad overlap in symptoms and consequences. This overlap occurs because both conditions involve a lack of sufficient magnesium (the extent to which each condition affects the body, however, can vary based on the severity and distribution of the magnesium shortfall).

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What Are the Symptoms of Magnesium Deficiency? 

The early symptoms of magnesium deficiency include: 

• Fatigue 
• Weakness 
• Loss of appetite 
• Nausea
• Vomiting

Beyond fatigue itself, nausea and vomiting may disrupt your sleep, adding to your tiredness.

As the deficiency gets worse, later symptoms of magnesium deficiency include: 

• Muscle contractions and cramps 
• Numbness
• Tingling
• Personality changes 
• Arrhythmia (abnormal heart rhythms) 
• Seizures 
• Coronary spasms (tightening in the arteries leading into the heart) 

Severe magnesium deficiency can cause: 

• Hypocalcemia (low calcium levels)
• Hypokalemia (low potassium levels) 

Habitually not getting enough magnesium from your diet or losing magnesium due to health issues can lead to magnesium deficiency. 

While nearly 50% of Americans don’t get enough magnesium from their diets, feeling symptoms of magnesium deficiency from low dietary intake is uncommon in otherwise healthy people, says the Office of Dietary Supplements at the National Institutes of Health (NIH). That’s because your kidneys limit the excretion of magnesium in your urine.  

How to Know if You Have a Magnesium Deficiency

To know if you have low magnesium levels or a magnesium deficiency, you’ll have to speak to a health professional. They can perform a series of checks along with evaluation of your diet and lifestyle and consideration of your clinical symptoms and risk factors.

The most common test is a blood test to check your serum magnesium concentration, or the magnesium levels in your blood. 

Normal serum magnesium levels are 1.46 to 2.68 mg per deciliter (mg/dL). Low magnesium is classed as less than 1.46 mg/dL. You may not feel symptoms until your magnesium levels are below 1.2mg/dL, however. It’s unclear when you’d start feeling fatigue as a symptom of low magnesium. 

Diagnosing a magnesium deficiency is tricky as you can have healthy levels of magnesium in the blood, but low levels elsewhere in your body. This is because serum magnesium levels only account for a small fraction of the body’s magnesium and your body taps into magnesium stores in your bones when needed. 

Your healthcare provider may also ask for a urine test or a magnesium red blood cell test to determine whether you have a magnesium deficiency. 

Symptoms aren’t always clear-cut, either. You may be getting enough magnesium to not feel serious symptoms of deficiency, but not enough to avoid some symptoms, like fatigue or other sleep and health issues.   

And it can be hard to tell yourself if you have a magnesium deficiency as many symptoms — like fatigue, muscle spasms, and loss of appetite — can be caused by other health issues or — in the case of fatigue — by simply not getting enough sleep at night. 

Heads-up: Most of us don’t know how much sleep we need, so may not be getting enough of it. Everyone needs a different amount of sleep and it can vary quite a bit. 

Among 1.95 million RISE users aged 24 and up, we found users need between five hours and 11 hours 30 minutes of sleep. Check RISE to find out how much sleep you personally need.

How to Get Enough Magnesium

Most people can get enough magnesium by eating magnesium-rich foods. 

Good sources of magnesium include:

• Leafy green vegetables like spinach  
• Legumes like lentils, edamame, and beans  
• Nuts and seeds like cashews and pumpkin seeds 
• Whole grains like brown rice and whole-wheat bread
• Fortified breakfast cereals  

How much magnesium you need depends on your age, sex, and whether you’re pregnant or breastfeeding, and it may be higher the more physically active you are. Your doctor can let you know how much magnesium you personally need. 

As a guideline, here’s the recommended dietary allowance (RDA) and adequate intake (AI) of magnesium from food and supplements combined. 

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Certain health conditions, stress, and medications can make it harder to get enough magnesium. They can impact magnesium absorption from the gut and how much magnesium your body holds onto. They can also all contribute to tiredness and sleep problems independently from affecting your magnesium levels. 

Speak to your doctor about getting enough magnesium if: 

• You have a gastrointestinal disease, like Crohn’s disease or celiac disease, or chronic diarrhea 
• You have type 2 diabetes
• You have an alcohol use disorder 
• You’re an older adult 
• You’re on medication like proton pump inhibitors or diuretics
• You’re under a lot of stress 

Your doctor may recommend magnesium supplements to help you get enough magnesium.

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Can Magnesium Supplements Make You Less Tired? 

Magnesium supplements may make you less tired. But they may only improve your tiredness if you have a magnesium deficiency or a sleep disorder or health issue that magnesium supplements can sometimes help with — like leg cramps, migraines, high blood pressure, or anxiety. 

It may also depend on your own biology, which type and how much magnesium you take, and whether something else is contributing to your tiredness. 

More research is needed, though. There aren’t many studies looking at magnesium and tiredness in the general population. Instead, they often focus on sub groups in specific populations. 

For example: 

• A 2011 study on women with breast cancer found magnesium supplements led to a reduction in hot flashes, sweating, and fatigue. 
• A 2014 study found magnesium supplements decreased lactate production, which can cause fatigue when exercising. 
• A 2024 study — which is currently undergoing review — on people with nonclinical insomnia symptoms found magnesium supplements led to better sleep duration, deep sleep, and sleep efficiency (how long you spend asleep in bed), which could lead to less tiredness.

Beyond looking at certain health conditions or situations, many magnesium studies are small, low quality, done on older adults, and use different types and amounts of magnesium, so we can’t say for sure whether they can improve your energy levels. 

Speak to your healthcare provider to find out if magnesium could make you less tired. They can recommend the best dosage and type of supplement — there are a lot to choose from, including magnesium sulfate, magnesium oxide, magnesium citrate, and magnesium chloride. They may also recommend another treatment. 

We’ve covered more on whether magnesium gives you energy here and how.

In some cases, magnesium supplements can make you more tired. Side effects from taking too much magnesium include nausea, vomiting, and abdominal cramps, and these side effects can disrupt your sleep.  

Taking very high doses of magnesium — typically more than 5,000 mg — is linked to magnesium toxicity, which can cause lethargy and muscle weakness as well as more serious side effects like cardiac arrest.

Expert tip: Taking magnesium supplements? RISE can help you make it a habit. You can get a notification on your phone, iPad, and Apple Watch when it’s time to start your bedtime routine, which you can use to remember to take magnesium. 

Causes of Tiredness Beyond Low Magnesium 

There are many reasons you could be feeling tired beyond low magnesium, including medical conditions, medications, stress, a poor diet, and hormone fluctuations. 

Two of the most common causes of tiredness are sleep debt (how much sleep you owe your body) and circadian alignment (how in sync you are with your circadian rhythm, or body clock). 

Lowering your sleep debt and getting in sync with your circadian rhythm can help you feel less tired. This is true for everyone, even if you don’t have low levels of magnesium. 

You may find sleep debt and being out of sync with your circadian rhythm are the reasons you feel tired, not low magnesium. Or they may be tanking your energy levels even further alongside a magnesium deficiency. 

If you lower your sleep debt and get in sync with your circadian rhythm, but still feel tired, speak to a healthcare provider to see if low magnesium or something else entirely is to blame. 

You can lower your sleep debt by: 

• Taking naps
• Going to bed a little earlier
• Sleeping in a little later
• Improving your sleep hygiene (the daily habits that help you fall and stay asleep)

You can get in sync with your circadian rhythm by: 

• Going to sleep and waking up at the same times each day 
• Eating meals at roughly the same times each day 
• Getting natural light first thing each morning and avoiding light before bed

RISE can tell you how much sleep debt you have and keep track as you chip away at it. 

It can also predict the timing of your circadian rhythm each day, so you more easily sync up. And RISE can tell you the best time to do 20+ sleep hygiene habits each day to help you get more sleep and, therefore, energy. 

If you’re curious about whether melatonin can help you feel less tired, we’ve covered magnesium vs. melatonin for sleep here. 

Low Magnesium Can Cause Tiredness  

Magnesium is an essential mineral and low magnesium levels are linked to fatigue, weakness, sleep problems, and health issues, which can cause sleep loss and low energy. But tiredness can also be caused by many other factors. 

Two of the most common causes of tiredness are sleep debt and being out of sync with your circadian rhythm. 

RISE can work out if you have any sleep debt and predict your daily circadian rhythm, so you can sync up with it. This can help you rule out these common causes or improve them to get more energy.

Users say: 

“You need this if you’re always tired. This app completely fixed my sleep schedule!...I never realized how deprived of sleep and unregulated my sleeping pattern was and to my surprise, once it was fixed I didn’t need coffee or a nap or anything else to have energy for the day.” Read the review. 

And RISE can help fast — 80% of RISE users feel less tired within five days.