Complete Testing & Optimization Guide
Optimal ranges, provider comparison, and strategies to improve your Magnesium levels
Included in 7 of 10 major testing providers
Electrolytes &Minerals
muscle and nerve function
Abnormal Magnesium levels can indicate underlying health issues that may go undetected without proper testing. Regular monitoring helps catch problems early when they're most treatable.
Understanding your Magnesium levels enables targeted interventions, tracks treatment effectiveness, and helps optimize your overall health and performance.
Magnesium is the fourth most abundant mineral in your body and is involved in over 300 enzymatic reactions, including energy production (ATP synthesis), DNA/RNA synthesis, protein synthesis, muscle and nerve function, blood pressure regulation, and glucose control. About 50-60% of your body's magnesium is stored in bones, 25% in muscles, and only 1% circulates in blood. This means serum magnesium (measured in standard blood tests) is a poor marker of total body magnesium status—you can be significantly deficient with "normal"serum magnesium.
Here's the critical insight:magnesium deficiency is epidemic. An estimated 50-75% of Americans don't meet the RDA for magnesium (420 mg/day for men, 320 mg/day for women), and up to 20% have overt deficiency. Modern agricultural practices have depleted soil magnesium, reducing food magnesium content by 30-50% over the past century. Processed foods, stress, alcohol, certain medications (PPIs, diuretics), and chronic diseases all further deplete magnesium. Yet magnesium deficiency is rarely diagnosed because serum magnesium doesn't drop until severe depletion—by the time serum magnesium is low, you're critically deficient.
Red blood cell (RBC) magnesium or ionized magnesium are more sensitive tests of intracellular magnesium status, but they're not routinely available. A better approach:if you have symptoms of magnesium deficiency (muscle cramps, insomnia, anxiety, arrhythmias, constipation) and normal serum magnesium, trial supplementation with 300-400 mg/day magnesium for 2-3 months. Most people benefit, and magnesium toxicity is rare with normal kidney function (excess is excreted).
Bottom line: TSH and Free T4 alone miss people with conversion problems. Free T3 is the only way to know if you have enough active thyroid hormone at the tissue level.
| Range Type | Level | Clinical Significance |
|---|---|---|
| Optimal (Longevity) | 2.2-2.6 mg/dL (serum) | Upper-normal range associated with better cardiovascular and metabolic health. Many functional medicine doctors target >2.2 mg/dL. |
| Adequate (Standard) | 1.8-2.2 mg/dL | Meets standard guidelines but may be suboptimal. Consider supplementation if symptoms (cramps, insomnia, anxiety) despite normal serum level. |
| Low-Normal (Suboptimal) | 1.5-1.8 mg/dL | Low-normal serum magnesium. Likely indicates tissue magnesium depletion. Supplement with 300-400 mg/day elemental magnesium. |
| Deficient | <1.5 mg/dL | Frank magnesium deficiency. Serum magnesium rarely drops this low unless severe depletion or renal wasting. Requires aggressive magnesium replacement (oral or IV). |
Standard lab range:muscle and nerve function
<1.2 mg/dL
High (Rare)
Hypermagnesemia. Rare unless severe kidney failure or excessive IV magnesium. Causes muscle weakness, hypotension, bradycardia, respiratory depression.
Magnesium glycinate:300-400 mg elemental magnesium daily. Most bioavailable, gentle on stomach, promotes relaxation and sleep. Preferred form for most people.
Magnesium citrate:300-400 mg daily. Good bioavailability, mild laxative effect (useful for constipation).
Magnesium threonate:2000 mg (144 mg elemental magnesium). Crosses blood-brain barrier, may improve cognitive function and sleep. More expensive.
Magnesium oxide:400-500 mg. Poorly absorbed (~4%), mainly used as laxative. Not recommended for magnesium repletion.
Magnesium malate:300-400 mg. May help with fibromyalgia and chronic fatigue.
Magnesium taurate:300-400 mg. May benefit cardiovascular health (taurine + magnesium synergy).
Topical magnesium (spray, lotion, Epsom salt baths):Absorbed through skin, bypasses GI. Useful adjunct but less reliable than oral.
Dark leafy greens:Spinach, Swiss chard, kale (high in magnesium, 150-200 mg per cooked cup).
Nuts and seeds:Almonds, cashews, pumpkin seeds, sunflower seeds (150-200 mg per ¼ cup).
Legumes:Black beans, chickpeas, lentils (100-120 mg per cup).
Whole grains:Brown rice, quinoa, oats (60-80 mg per cup). Refined grains lose 80-90% of magnesium.
Dark chocolate:70-85% cacao (60-100 mg per oz).
Avocado:1 medium avocado ~60 mg.
Fatty fish:Mackerel, salmon (40-60 mg per 3 oz).
Hard water:Some tap water contains 10-30 mg magnesium per liter (varies by region).
Note: Vitamin D:Magnesium is required for vitamin D activation (25(OH)D → 1,25(OH)2D). Vitamin D supplementation without magnesium can worsen deficiency. | Vitamin B6:Enhances magnesium uptake into cells. | Avoid magnesium inhibitors:Alcohol, caffeine (>3 cups coffee/day), high-dose zinc (>50 mg), high-calcium diets (>2000 mg/day) compete with or deplete magnesium. | Adequate protein:Magnesium absorption requires adequate protein intake. | Probiotics and gut health:Healthy gut microbiome enhances magnesium absorption. Dysbiosis impairs absorption.
Note: PPIs (omeprazole, pantoprazole):Long-term use (>1 year) impairs magnesium absorption. Check magnesium annually, supplement if needed. | Diuretics:Loop diuretics (furosemide) and thiazides cause urinary magnesium wasting. Supplement with 300-400 mg/day. | Bisphosphonates (alendronate, risedronate):Used for osteoporosis, can lower magnesium. | Antibiotics:Aminoglycosides, fluoroquinolones increase urinary magnesium loss. | Chemotherapy:Cisplatin, carboplatin cause severe magnesium wasting.
Muscle weakness, fatigue|Nausea, vomiting|Hypotension (low blood pressure)|Bradycardia (slow heart rate)|Flushing, warmth|Loss of deep tendon reflexes|Respiratory depression (if severe)|Cardiac arrest (if very severe, >7 mg/dL)
Source:Hypermagnesemia is rare and occurs only with severe kidney failure, excessive IV magnesium, or massive oral intake (laxative abuse). Normal kidneys excrete excess magnesium.
Kidney failure (end-stage renal disease):Kidneys can't excrete magnesium, causing accumulation.|Excessive IV magnesium:Iatrogenic (medical error) or pre-eclampsia treatment.|Massive oral intake:Laxative abuse (milk of magnesia, Epsom salt ingestion). Requires >5000 mg/day with normal kidney function.|Rare:Hypothyroidism, Addison's disease (reduce renal excretion).
Source:Baseline:Check serum magnesium if symptoms (cramps, insomnia, arrhythmias, anxiety) or risk factors (on PPIs/diuretics, type 2 diabetes, chronic diarrhea).|RBC magnesium:More accurate reflection of intracellular status if available. Normal 4.0-6.5 mg/dL.|After starting supplementation:Retest serum magnesium after 3 months. Goal >2.0 mg/dL. If symptoms resolve, continue maintenance dose (300-400 mg/day).|Annual screening:For patients on chronic PPIs, diuretics, or with type 2 diabetes.|If low serum magnesium (<1.5 mg/dL):Also check potassium and calcium (often co-deficient). Correct magnesium first, as magnesium deficiency impairs potassium repletion.
~50% of Americans consume less than the RDA for magnesium (420 mg men, 320 mg women). Up to 20% have overt deficiency based on dietary surveys. Serum magnesium underestimates true prevalence because it's tightly regulated;tissue depletion occurs first.
Source:Rosanoff A, et al. Suboptimal magnesium status in the US:are the health consequences underestimated? Nutr Rev. 2012;70(3):153-164.
Magnesium deficiency is associated with hypertension, arrhythmias, coronary artery disease, and sudden cardiac death. Meta-analyses show magnesium supplementation (300-400 mg/day) lowers systolic BP by 3-5 mmHg and diastolic BP by 2-3 mmHg. Higher dietary magnesium intake associated with 30% lower CVD risk.
Source:Zhang X, et al. Effects of magnesium supplementation on blood pressure:a meta-analysis. Hypertension. 2016;68(2):324-333.
Low magnesium intake and serum levels strongly associated with insulin resistance and type 2 diabetes (2-3x higher risk). Magnesium is required for insulin receptor function and glucose transport. Magnesium supplementation (300-400 mg/day) improves insulin sensitivity, fasting glucose, and HbA1c in diabetics and prediabetics.
Source:Larsson SC, Wolk A. Magnesium intake and risk of type 2 diabetes:a meta-analysis. J Intern Med. 2007;262(2):208-214.
| Provider | Includes Test | Annual Cost | Total Biomarkers |
|---|---|---|---|
 Superpower | ✓ | $199 | 100+ |
 WHOOP Advanced Labs | — | $349 | 65 |
 Labcorp OnDemand | — | $398 | 30+ |
| ✓ | $486 | 40+ | |
| — | $468 | 83 | |
| ✓ | $798 | 100+ | |
 InsideTracker | ✓ | $680 | 48 |
 Function Health | ✓ | $499 | 100+ |
| ✓ | $900 | 70+ | |
| ✓ | $1150 | 110 | |
| — | $Varies | 75+ |
Choose from 7 providers that include this biomarker in their panels
Magnesium is a electrolytes &minerals biomarker that Mineral involved in 300+ biochemical reactions The normal reference range is muscle and nerve function. Regular testing helps track changes and identify potential health issues early.
7 out of 10 major blood testing providers include Magnesium in their standard panels. These include Superpower, Blueprint, Mito Health and others.
For most people, testing Magnesium 2-4 times per year is recommended to establish baseline levels and track trends. If you have abnormal results or are actively working to optimize this biomarker, more frequent testing (quarterly) may be beneficial. Always consult with your healthcare provider for personalized testing frequency recommendations.
The standard laboratory reference range for Magnesium is muscle and nerve function. However, many functional medicine practitioners recommend tighter "optimal" ranges for peak health and performance. Your ideal range may vary based on your age, sex, health goals, and other individual factors. Work with a healthcare provider familiar with optimal ranges to determine your target levels.
Most direct-to-consumer blood testing services that include Magnesium provide the physician order as part of their service. However, some states have restrictions on direct-to-consumer testing. Check with your chosen provider about availability in your state and whether they provide the necessary physician authorization.
Essential for energy production
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs and before making decisions about blood testing.
