Magnesium: What It Is, Why It Matters, and How to Optimize Your Levels

Magnesium is an essential mineral, meaning your body needs it to function properly but cannot produce it on its own. It's abundant in the body, primarily stored in bones, muscles, and soft tissues. [1] Less than 1% of the body's total magnesium is found in the blood, and these levels are tightly regulated. [1]

Magnesium plays a vital role in numerous physiological processes, acting as a cofactor in more than 300 enzyme systems that regulate diverse biochemical reactions. [1] These include energy production, muscle and nerve function, bone health, blood sugar and blood pressure regulation, protein synthesis, DNA and RNA synthesis, and electrolyte balance. [1]

Measurement Type	Normal Range
Serum Magnesium	1.7 to 2.2 mg/dL (0.70 to 0.91 mmol/L)

• Reference ranges may vary slightly depending on the laboratory [2].

Important Considerations

• Blood levels vs. total magnesium:
  • Most magnesium is stored in bones and inside cells, not in the bloodstream [1].
  • Serum levels may not fully reflect total body magnesium status [1].

Factors That Influence Magnesium Levels

Factor	How It Affects Magnesium
Dietary intake	The amount of magnesium consumed through food directly impacts overall levels [1].
Kidney function	Kidneys regulate magnesium balance by controlling excretion [1].
Gastrointestinal absorption	Conditions affecting digestion can limit how well magnesium is absorbed [1].
Certain medications	Some drugs can increase loss or reduce absorption of magnesium [1].
Underlying medical conditions	Chronic conditions may disrupt magnesium balance in the body [1].

Magnesium levels can become imbalanced due to a variety of factors, leading to either deficiency (hypomagnesemia) or excess (hypermagnesemia).

Low Magnesium: Causes and Risk Factors

Magnesium deficiency is uncommon in healthy individuals, but it can occur due to the following [1,3,4]:

• Insufficient dietary intake: Not consuming enough magnesium-rich foods.
• Gastrointestinal issues: Conditions such as Crohn’s disease, celiac disease, chronic diarrhea, inflammatory bowel disease, or malabsorption syndromes can impair absorption.
• Kidney problems: Certain kidney disorders or medications can lead to excessive magnesium loss through urine.
• Alcohol abuse: Chronic alcohol use can reduce absorption and increase excretion.
• Certain medications: Diuretics, proton pump inhibitors, and some antibiotics may increase magnesium loss.
• Chronic health conditions: Conditions like type 2 diabetes and pancreatitis can contribute to lower levels.

High Magnesium: Causes and Risk Factors

High magnesium levels are less common and are typically caused by the following [5,6]:

• Kidney failure: The most common cause, as impaired kidneys cannot effectively remove excess magnesium.
• Excessive intake from supplements or medications: Overuse of magnesium-containing supplements, antacids, or laxatives can lead to elevated levels.
• Certain endocrine disorders: Conditions such as hypothyroidism and Addison’s disease may be associated with higher levels.

Both low and high magnesium levels can cause a range of symptoms affecting multiple systems in the body.

Symptoms of Deficiency (Low Magnesium)

Early symptoms may include [7]:

• Loss of appetite
• Nausea and vomiting
• Fatigue
• Weakness
• Muscle cramps or twitching

As deficiency progresses, symptoms may include [7]:

• Abnormal heart rhythms (arrhythmias)
• Seizures
• Electrolyte imbalances (low calcium and potassium levels)

Symptoms of Excess (High Magnesium)

Common symptoms include [6]:

• Nausea
• Diarrhea
• Flushing
• Low blood pressure (hypotension)
• Confusion
• Muscle weakness

In more severe cases, symptoms may include [6]:

• Difficulty breathing
• Cardiac arrest

If you’re experiencing any of these symptoms or suspect your magnesium levels may be imbalanced, it’s important to consult your healthcare provider for proper evaluation, testing, and guidance.

Management and treatment of magnesium imbalances depend on whether levels are too low or too high, as well as the severity of the condition.

Dietary Adjustments and Supplementation

For mild deficiency or maintaining optimal levels, dietary changes are often the first step. Magnesium-rich foods include [1,3,8]:

• Dark leafy greens (spinach, kale)
• Nuts (almonds, cashews, Brazil nuts) and seeds (pumpkin, chia, flax)
• Legumes (black beans, lentils, chickpeas)
• Whole grains (brown rice, quinoa, whole-wheat bread)
• Avocados and bananas
• Fatty fish like salmon and halibut

Magnesium supplements are available in various forms (e.g., oxide, citrate, chloride), with liquid-soluble forms generally better absorbed [1]. Always consult a healthcare provider before starting supplements, as excessive intake can cause adverse effects [6].

Medications and Clinical Treatment

For Low Magnesium:

• Oral magnesium supplements are typically the first-line treatment for symptomatic deficiency [3].
• Intravenous (IV) magnesium may be used in severe cases or when oral supplementation is not possible [3].
• Addressing underlying causes—such as malabsorption or medication effects—is essential [5].

For High Magnesium:

• Discontinuing magnesium-containing medications or supplements is the first step.
• Additional treatments may include IV fluids, diuretics, calcium administration, or dialysis in severe cases [6].

Testing magnesium levels can provide valuable insight into your overall health, especially if you are experiencing symptoms or have risk factors for an imbalance.

How it’s tested: The most common method is a blood test that measures serum magnesium [5]. While tightly regulated, serum levels may not fully reflect total body stores, as most magnesium is found in bones and inside cells [1]. In some cases, additional tests—such as a 24-hour urine collection or a red blood cell magnesium test—may be used for a more comprehensive assessment [1].

When/why someone should test: Testing may be recommended if you have symptoms of deficiency or excess, underlying conditions like kidney disease or chronic digestive disorders, or are taking medications (such as certain diuretics) that can affect magnesium levels [4]. It may also be included as part of a broader health evaluation to monitor nutrient status and overall well-being.

At-home testing options: At-home magnesium tests are available and can offer a convenient way to check levels. However, their accuracy and interpretation may vary compared to traditional lab-based testing. Abnormal results should be discussed with a healthcare provider and confirmed with clinical laboratory testing.

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