12 Signs and Symptoms of Magnesium Deficiency

magnesium deficiency test magnesium deficiency test

Magnesium deficiency is surprisingly common with up to 50% of the population not getting enough magnesium in their diets. Some mistake the signs and symptoms for other ailments, while others don’t notice the symptoms at all. Given that magnesium deficiency carries some serious health risks, it’s important to know how to tell if you have it. To help you out, we’ve rounded up 12 common signs and symptoms of magnesium deficiency. 

Why is magnesium deficiency a big deal? 

Magnesium is an essential mineral involved in over 300 biochemical reactions in the body. It plays a major role in things like: 

  • Heartbeat, rhythm, and function 
  • Blood pressure regulation 
  • Blood sugar control 
  • Protein synthesis (creation)
  • DNA and RNA synthesis 
  • Energy synthesis 
  • Nerve impulses 
  • Muscle contraction
  • Bone development 
  • Immune system function
  • Antioxidant production 

When you don’t get enough magnesium, every single one of those important functions is affected. As you’ll learn in this article, that can lead to conditions like cardiovascular disease, type 2 diabetes, depression, anxiety, migraines, premenstrual syndrome (PMS), Alzheimer’s disease, and ADHD

How do I know if I have a magnesium deficiency? 

It’s hard to tell for sure if you have a magnesium deficiency. And unfortunately, medical tests for magnesium deficiency are hard to access and generally unreliable. 

Your magnesium levels are measured with a simple blood test called a serum magnesium test. The normal range you’d expect to see in a healthy person would be anywhere between 0.7-1.0 mmol/L. If your result was below 0.7, you’d be considered to have a magnesium deficiency, also called hypomagnesemia. Above 1.0 would mean too much magnesium or hypermagnesemia

It sounds straightforward, but many experts agree that the 0.7 threshold for magnesium is far too low. A subclinical deficiency is one that’s low enough to cause problems, but not low enough to pass that official threshold. For magnesium, subclinical deficiency is thought to begin at about 0.8, and it’s so risky to your health that one team of experts calls it “a public health crisis”. 

So how can you tell? The scary thing about subclinical magnesium deficiency is that it’s often silent. Some people put symptoms like fatigue and weakness down to the stresses of day-to-day life, while others don’t notice any symptoms at all. The best ways to protect yourself from magnesium deficiency are to understand your risk factors and know the signs and symptoms to look out for. 

Risk factors for magnesium deficiency 


The biggest risk factor for magnesium deficiency is your diet. You’re likely to be deficient if you don’t eat enough magnesium-rich foods like leafy greens, whole grains, and oily fish. But even if you do, food quality isn’t what it used to be! 

Experts say that the magnesium content of plants has dramatically declined in recent years, partly thanks to poor soil quality and contamination. Heavy processing, like refining whole wheat to make white pasta and bread, also depletes magnesium. So by the time your food reaches your plate, it might not have anywhere as much magnesium as you expect it to. 

Your intake of other nutrients can affect how magnesium is absorbed or used by your body. If you have the following, you’re at greater risk of magnesium deficiency:

Health conditions

Certain health conditions can affect how your body absorbs, uses, or gets rid of magnesium. For example: 

  • Stress depletes magnesium levels and reduces magnesium absorption.
  • Gastrointestinal disorders like Crohn’s, celiac disease, and ulcerative colitis can interfere with magnesium absorption. 
  • Kidney problems or type 2 diabetes cause greater magnesium loss by increasing urination. 
  • Alcoholism affects magnesium levels in different ways, e.g. vomiting prevents absorption, and kidney disease increases loss. 
  • Pregnancy diverts magnesium to your growing baby, so you need more to meet your own needs. 


Some medications can also affect how magnesium is absorbed, how it behaves in your body, and/or how easy it is to get rid of.  The most commonly affected meds include: 

  • Diuretics (for water retention or kidney problems)
  • Proton-pump inhibitors (for acid reflux or stomach ulcers)
  • Anti-diabetic medications (e.g. insulin)
  • Antibiotic and antiviral medications
  • Bronchodilators (for asthma and other respiratory problems)
  • Bisphosphonates (for osteoporosis)
  • Heart medications 
  • Chemotherapy drugs 
  • Immunosuppressants 


Older people are at higher risk of magnesium deficiency for a couple of reasons: our appetite gets lighter as we age, our digestive system gets less efficient, and we naturally lose magnesium from our bone stores. We’re also more likely to suffer from health conditions or take medications that affect magnesium (see above). 

Children and teens are at very high risk of magnesium deficiency, too. They need much more magnesium to support their growth and development, but magnesium-rich foods like spinach and oily fish aren’t typically kid-friendly favorites! 

If you (or your loved ones) have any of these risk factors, there’s a strong possibility that you could have a magnesium deficiency. Read on for the most common signs and symptoms of magnesium deficiency to be on the lookout for…

What are the signs & symptoms of magnesium deficiency?

Muscle aches, cramps, or twitches

In order to move a muscle properly, you need calcium to make it contract, and magnesium to make it relax. If you don’t have enough magnesium available, this delicate balance is thrown off, causing the muscle to involuntarily twitch, spasm or seize up. So if you’re experiencing regular twitches or cramps, that could be your muscles crying out for more magnesium!

Deficiency is commonly associated with night-time leg cramps and restless leg syndrome (RLS), and supplements have been successfully used to reduce the frequency and intensity of leg cramps in pregnant women. 

MORE: Magnesium for leg cramps: does it help?

Chronic pain 

Longer-term muscular pain is associated with chronic inflammation in the body, which is another possible sign of magnesium deficiency. Inflammation is a normal immune response to injury or infection, and it’s fine in small doses. However, in some people, this response can become permanently “switched on”, causing tissue damage and ongoing pain.  

Magnesium has been shown to target inflammation at a genetic level, and magnesium chloride and magnesium citrate specifically have both been shown to decrease markers of inflammation in the blood. Magnesium malate has been found to significantly improve muscle pain in people with fibromyalgia and reduce the number of tender spots around the body. Magnesium chloride has also been shown to reduce muscle pain in fibromyalgia sufferers and has been used to successfully treat chronic muscle pain in a child that hadn’t responded to any other treatments.  

MORE: Magnesium for fibromyalgia: can magnesium help with pain?

Low mood or anxiety

You need magnesium to create serotonin, a neurotransmitter that regulates anxiety and promotes feelings of happiness and well-being. Low serotonin levels are associated with various mood disorders, and lots of medications for these conditions actually work by preventing your serotonin levels from dropping. If you’re finding yourself anxious, low, apathetic, or unusually emotional, it may be a sign that you don’t have enough magnesium to produce the serotonin you need. 

Research does show a strong link between depression and anxiety. In an analysis of over 8,800 people, those with the lowest magnesium intake were found to have a 22% higher risk of depression. In an animal study, previously healthy rats developed anxiety when only one thing was changed — their magnesium intake. Various other studies found that magnesium supplements: 

MORE: Magnesium for anxiety: can magnesium help relax?

AND: Magnesium for depression: can magnesium help lift your mood?

Trouble sleeping 

Your natural sleep-wake cycle is controlled by your circadian clock, which uses certain hormones to signal when it’s time to wake up, and when it’s time to hit the hay. Magnesium helps that clock to “keep time” and regulates those sleep-wake hormones. It’s also involved in activating your parasympathetic nervous system. This is your body’s a restful, relaxed state — the opposite of the sympathetic nervous system that kicks into gear when you’re stressed. And finally, magnesium acts on receptors for GABA, a neurotransmitter that calms the brain and prepares you for sleep. With so many important roles in the sleep process, it’s no surprise that insomnia is often a sign of magnesium deficiency.

Magnesium — especially magnesium glycinate — has long been a go-to remedy for those struggling to get a good night’s sleep. Magnesium glycinate contains glycine, a natural amino acid known to calm the brain, improve sleep quality in people with insomnia, and reduce next-day mental fatigue and sluggishness. Magnesium glycinate supplements have been shown to help people fall asleep faster, sleep longer, and feel more deeply rested. 

MORE: Can magnesium help you sleep?

Fatigue and weakness 

Before the food you eat can be used for energy, a complex series of chemical reactions must take place. We won’t go into the details! But the end result is a molecule called ATP, which captures the energy from your food, shuttles it around your body and delivers it into your cells. 

In order to do this properly, ATP needs to be bound to magnesium. A lack of magnesium, then, can limit the amount of energy available to every cell in your body. That’s why chronic fatigue, low energy, and general weakness are often telltale signs of a magnesium deficiency.

MORE: Can magnesium help with fatigue?

Poor exercise performance 

Because magnesium is so important for energy production, it makes sense that a deficiency would show up during exercise when your energy needs are much higher. Your body typically needs up to 20% more magnesium during a workout, helping to make more glucose available and clear the extra metabolic waste from your muscles. So if you’re finding your muscles tire easily, cramp up, or take a while to recover, magnesium deficiency could be the culprit. 

Athletes have known this for a long time, and various studies back it up. A group of volleyball players boosted their anaerobic metabolism and key movements with daily magnesium supplements, and a group of triathletes found that magnesium orotate improved their performance in all three activities, along with other major benefits. 

Non-athletes can benefit too, with elderly women who took magnesium oxide showing improved exercise ability and performance. Patients with the chronic obstructive pulmonary disease also found their lung function and exercise performance improved. 

Trouble focusing

Your ability to perform your day-to-day tasks depends on cognitive functions like focus, attention, memory, and learning. In turn, these functions depend on healthy neurons (brain cells) that can effectively communicate with each other. And as you’ve probably guessed by now, that depends on magnesium! If you’re struggling to stay focused, concentrate on demanding tasks, or just remember where you put those damn keys (hi!), it could be a sign that you’re lacking in this essential mineral. 

That seems to be at least partly the case in Attention Deficit Hyperactivity Disorder (ADHD). One study reported magnesium deficiency in 72% of children suffering from ADHD. The research team found that cognitive function improved when the kids were given magnesium supplements, and another study found that supplements reduced hyperactivity.

If you’re looking to fight brain fog, the best type of magnesium supplement to go for is magnesium L-threonate. It was specially designed by MIT scientists to cross the blood-brain barrier, something other types of magnesium don’t do quite as well. The result is a supplement with countless animal studies demonstrating its cognitive benefits (here, here, here, here, and here), as well as a landmark human study in which it actually reversed cognitive decline associated with aging!


Migraines can be debilitating for some people, and we’re still not exactly sure why they happen. What we do know is that sufferers are more likely to have a magnesium deficiency. So if your migraines are getting stronger or more frequent, it may be a warning sign. 

Research shows that magnesium supplementation can reduce the frequency and severity of migraine attacks. This study, this one, and this one all found that magnesium citrate reduced the frequency of migraine attacks by as much as 41.6%. When given magnesium oxide, children suffering from migraines experienced fewer “headache days”. And magnesium sulfate has been shown to be even more effective than a common migraine medication for rapid relief. 

MORE: Magnesium for migraines: Can magnesium help with headaches?

Severe premenstrual syndrome (PMS)

In the run-up to their period, many women experience some degree of PMS. This is a collection of symptoms that can include things like bloating, mood swings, anxiety, headaches, and insomnia, and they can range from mild to severe. 

You might notice that many of those are also signs of a magnesium deficiency, and research does in fact show that low magnesium levels are associated with PMS. If you’re finding that your monthly PMS symptoms are getting too much to handle, then, this could be at least partly linked to a lack of magnesium. 

Luckily, magnesium supplements have been shown to help symptoms like mood swings, depressive episodes, and fluid retention. They’re believed to be especially effective when you take them alongside vitamin B6

MORE: Magnesium and vitamin B6: should you take them together? 

Frequent infections 

If you’re always catching colds and other bugs, this could be a sign of magnesium deficiency. Magnesium is needed to create certain immune cells that protect us from infection. Not only that, those cells actually need a certain level of magnesium before they can neutralize a threat. Researchers have found, for example, that T cells can only eliminate infections in a magnesium-rich environment.

High blood pressure 

Magnesium helps to regulate most aspects of your cardiovascular system, including blood pressure, so high blood pressure is a possible warning sign of magnesium deficiency. Symptoms include strong headaches, dizziness, breathlessness, vision problems, flushing, or any unusual or painful sensations in your chest.

Study after study (more here, here, and here!) has shown that magnesium has a positive, lowering effect on blood pressure, and the higher the blood pressure, the greater the benefit. However, high blood pressure could indicate a serious underlying problem and increases your risk of cardiovascular disease or stroke. So if you do notice these symptoms, your first stop should be your doctor. 

Irregular heartbeat 

An irregular heartbeat, also called arrhythmia, is one of the most serious signs of magnesium deficiency. In one study of patients admitted to the hospital with arrhythmia, 38% had a clinical magnesium deficiency and 72% were losing too much magnesium. 

The most common symptom of arrhythmia is palpitations, which can feel like your heart is suddenly beating rapidly, before calming down again. Some people describe it as a fluttering sensation, or feeling like your heart has “missed a beat”. Other possible symptoms are chest pain, lightheadedness, shortness of breath, or fainting.

Magnesium supplementation has been shown to improve arrhythmia, but if you are experiencing symptoms, the first and most important thing to do is to seek medical advice. Arrhythmia can seriously increase the risk of heart failure, heart attack, and stroke, and, like high blood pressure, there may be another underlying problem that needs to be addressed.

MORE: Magnesium: Is it good for heart health?

How can I treat magnesium deficiency? 

The best way to boost your magnesium levels is to pack your diet with magnesium-rich foods. However, if you find that you’re still not getting enough, then magnesium supplements are a great way to bridge the gap.  

Magnesium supplements usually come as a compound, which means they’re combined with other ingredients that each have their own unique benefits. One example is magnesium taurate, made with an amino acid called taurine that’s known to promote heart health.

Read our comparison of the different types of magnesium supplements.

How much magnesium should I take? 

The recommended magnesium dosage and intake vary depending on your age and sex. The table below shows the adequate intake (AI) and recommended dietary allowance (RDA) from the National Institute of Health.

Birth to 6 months30 mg*30 mg*
7–12 months75 mg*75 mg*
1–3 years80 mg80 mg
4–8 years130 mg130 mg
9–13 years240 mg240 mg
14–18 years410 mg360 mg
19–30 years400 mg310 mg
31–50 years420 mg320 mg
51+ years420 mg320 mg

Are magnesium supplements safe? 

Yes, for most people. The most common side effects are nausea, cramps, and diarrhea, but you can reduce the risk by sticking to the recommended dose and taking an easily absorbed, well-tolerated form like magnesium glycinate

Magnesium could cause more serious side effects in people who take certain medications or have health problems. An example is kidney disease, which might make it hard for your body to flush out excess magnesium. It’s best to check with your doctor before taking any supplements just to make sure you can take them safely. 

If you’re worried about magnesium deficiency due to symptoms like depression, chest pain, palpitations, breathlessness, dizziness, or fainting, it’s important to seek medical advice quickly. While you may indeed have a magnesium deficiency, you may also have a serious condition that needs medical attention. Best to err on the safe side!