Magnesium: The Most Common Deficiency You've Never Been Tested For

Magnesium is involved in over 300 enzymatic reactions in your body. It's essential for energy production, muscle function, nerve signalling, and DNA synthesis. Yet it's rarely tested—and when it is, the standard test often misses deficiency entirely.

Only 1% of your body's magnesium is in your blood. The rest is in your bones, muscles, and cells. Your body works hard to maintain serum levels, pulling from tissue stores when necessary.

This means you can have a "normal" serum magnesium while being significantly depleted at the cellular level. By the time serum magnesium drops, you're severely deficient.

A more accurate assessment is RBC (red blood cell) magnesium, which reflects intracellular stores. This is the marker we include in our Metabolic Audit panel.

Optimal RBC Magnesium Levels

• Optimal: 6.0-6.5 mg/dL
• Acceptable: 5.5-6.0 mg/dL
• Low: Below 5.5 mg/dL

Because magnesium affects so many systems, deficiency symptoms are varied:

Muscular

• Muscle cramps and twitches
• Tension and tightness
• Restless legs
• Eye twitching

Neurological

• Anxiety and irritability
• Poor stress tolerance
• Insomnia or poor sleep quality
• Headaches and migraines

Cardiovascular

• Heart palpitations
• High blood pressure
• Irregular heartbeat

Metabolic

• Fatigue and low energy
• Blood sugar dysregulation
• Poor exercise recovery

Modern factors deplete magnesium:

• Soil depletion — Crops contain less magnesium than historically
• Processed foods — Refining removes magnesium
• Stress — Cortisol increases magnesium excretion
• Caffeine and alcohol — Both deplete magnesium
• Certain medications — PPIs, diuretics, antibiotics
• Intense exercise — Lost through sweat

Magnesium-rich foods include:

• Dark leafy greens (spinach, Swiss chard)
• Nuts and seeds (pumpkin seeds, almonds)
• Dark chocolate (70%+ cacao)
• Avocados
• Legumes
• Whole grains

However, even with good dietary intake, many people benefit from supplementation due to the factors above.

Not all magnesium supplements are equal. Forms differ in absorption and effects:

• Magnesium glycinate — Well-absorbed, calming, good for sleep
• Magnesium citrate — Good absorption, can loosen stools
• Magnesium threonate — Crosses blood-brain barrier, cognitive benefits
• Magnesium oxide — Poorly absorbed, mainly laxative effect

The right form depends on your primary symptoms and goals.

For anyone dealing with muscle tension, poor recovery, sleep issues, or stress-related symptoms, magnesium status should be investigated. It's one of the most impactful and well-tolerated interventions we recommend—and often produces noticeable benefits within days to weeks.