Magnesium Deficiency: How to Spot the Signs and Why It Matters

If you experience muscle cramps, have trouble sleeping, feel anxious for no clear reason, or struggle with low energy, there is a good chance magnesium plays a role. This essential mineral is involved in over 300 enzymatic reactions in your body, yet the majority of people do not get enough of it.

Magnesium deficiency is so widespread that some researchers call it a public health crisis hiding in plain sight. Understanding what magnesium does, recognising the signs of deficiency, and knowing how to optimise your levels can make a meaningful difference in how you feel.

What Magnesium Does in Your Body

Magnesium is not a one-trick mineral. It is involved in:

Energy production. Magnesium is essential for the production of ATP, your body's energy currency. Without adequate magnesium, you simply cannot produce energy efficiently.

Muscle and nerve function. Magnesium regulates muscle contraction and relaxation, including your heart muscle. It also influences nerve transmission throughout your body.

Blood sugar regulation. Magnesium plays a role in insulin signalling and glucose metabolism. Deficiency is associated with insulin resistance.

Blood pressure regulation. Magnesium helps relax blood vessels, supporting healthy blood pressure.

Bone health. About 60% of your body's magnesium is stored in bones. Magnesium is essential for calcium absorption and bone formation.

Sleep and relaxation. Magnesium activates the parasympathetic nervous system (rest-and-digest) and regulates neurotransmitters involved in sleep.

Mood regulation. Magnesium influences serotonin and other neurotransmitters. Deficiency is linked to anxiety and depression.

Protein synthesis. Your body needs magnesium to build proteins, including for tissue repair and muscle building.

Given this wide-ranging involvement, it is not surprising that deficiency affects so many aspects of health.

Why Deficiency Is So Common

Several factors contribute to widespread magnesium deficiency:

Depleted soils. Modern agricultural practises have depleted magnesium from soils, meaning crops contain less than they once did.

Processed food diets. Refining grains removes most of their magnesium content. Diets heavy in processed foods provide little magnesium.

Stress. Stress increases magnesium excretion while also increasing the body's magnesium requirements. Chronic stress creates a double burden.

Certain medications. Proton pump inhibitors (acid blockers), diuretics, and some antibiotics can deplete magnesium.

Gut issues. Conditions affecting the gut (Crohn's, celiac disease, even less obvious gut dysfunction) impair magnesium absorption.

Alcohol. Regular alcohol consumption increases magnesium excretion.

Age. Magnesium absorption decreases with age, while requirements may increase.

Sweating. Athletes and those who sweat heavily lose magnesium through perspiration.

Signs of Magnesium Deficiency

Because magnesium is involved in so many processes, deficiency can show up in many ways:

Physical Signs

• Muscle cramps, spasms, or twitches
• Eye twitching
• Restless legs
• Tension headaches or migraines
• Constipation
• Fatigue and low energy
• Numbness or tingling
• Irregular heartbeat or palpitations
• High blood pressure

Mental and Emotional Signs

• Anxiety or nervousness
• Difficulty relaxing
• Depression or low mood
• Irritability
• Difficulty concentrating
• Brain fog

Sleep-Related Signs

• Difficulty falling asleep
• Difficulty staying asleep
• Unrefreshing sleep
• Restless legs at night

Many of these symptoms are vague and easily attributed to other causes, which is why magnesium deficiency often goes unrecognised. If you have several of these symptoms, magnesium is worth considering.

Testing for Magnesium Deficiency

Here is something important to understand: standard blood tests for magnesium are not very useful. Less than 1% of your body's magnesium is in the blood - the vast majority is in cells and bones. Blood levels are tightly regulated and can appear normal even when total body magnesium is depleted.

More accurate tests include:

• RBC (red blood cell) magnesium - measures magnesium inside cells, giving a better picture of status
• Magnesium loading test - measures how much magnesium your body retains versus excretes

However, given how safe magnesium supplementation is for most people and how common deficiency is, many practitioners recommend a trial of supplementation based on symptoms rather than waiting for definitive testing.

Increasing Your Magnesium

Food Sources

Foods rich in magnesium include:

• Dark leafy greens (spinach, Swiss chard)
• Nuts and seeds (pumpkin seeds, almonds, cashews)
• Dark chocolate (a legitimate health food in moderation)
• Avocados
• Legumes
• Whole grains
• Fatty fish

Eating a diet rich in whole foods naturally increases magnesium intake, though it may be difficult to reach optimal levels through food alone given soil depletion and modern diets.

Supplementation

Magnesium supplements come in many forms, with different absorption rates and effects:

Magnesium glycinate - well-absorbed, gentle on the stomach, and has calming properties (from the glycine). Good for sleep and anxiety.

Magnesium citrate - well-absorbed and can have a mild laxative effect. Good for those with constipation.

Magnesium threonate - specifically researched for brain health and cognitive function. May cross the blood-brain barrier more effectively.

Magnesium malate - often recommended for muscle pain and fatigue.

Magnesium oxide - inexpensive but poorly absorbed. Often used as a laxative.

Magnesium taurate - combines magnesium with taurine, often recommended for heart health.

Topical magnesium (oils, lotions, bath salts) - absorbed through the skin, useful for targeted muscle relief and for those who do not tolerate oral supplements well.

Start with a moderate dose and increase gradually. Too much too fast can cause loose stools (your body's way of excreting excess). Most adults benefit from 200-400mg of elemental magnesium daily from supplements, in addition to dietary sources.

Other Considerations

Vitamin D increases magnesium utilisation, which is why some people experience muscle cramps when starting vitamin D without also increasing magnesium.

Calcium and magnesium work together. Very high calcium intake without adequate magnesium can create imbalance.

Certain conditions require caution with magnesium supplementation, including kidney disease. Check with your healthcare provider if you have kidney issues.

The Bottom Line

Magnesium deficiency is common, often unrecognised, and contributes to a wide range of symptoms that many people accept as normal. The good news is that it is relatively easy to address - and the benefits of optimising magnesium can be significant.

If you struggle with muscle cramps, sleep issues, anxiety, fatigue, or constipation, magnesium is worth exploring. It is inexpensive, generally safe, and for many people, it makes a noticeable difference in how they feel.

Want to learn more about nutrients and energy? Explore natural supplements for fatigue or understand the causes of fatigue.