Research Blog

November 11, 2022

Mineral Biomarkers: Serum Magnesium

Optimal Takeaways

Magnesium is a critically important mineral as it has antioxidant and anti-inflammatory properties and is a cofactor for more than 600 metabolic enzymes. It is especially important to cardiovascular health, neurological function, bone integrity, and glucose regulation. Low magnesium is associated with hypertension, cardiac arrhythmias, CVD, osteoporosis, glucose dysregulation, inflammation, headaches, depression, cognitive impairment, sleep disturbance, muscle cramps, and kidney stones. Hypermagnesemia is uncommon but can occur with excessive intake or reduced kidney excretion.

Conventional Lab Range: 1.50 - 2.50 mg/dL (0.62 - 1.04 mmol/L)

Optimal Dx’s Optimal Range: 2.20 - 2.50 mg/dL (0.91 - 1.04 mmol/L)

Low magnesium is associated with inadequate intake, malnutrition, malabsorption, hypoparathyroidism, diabetic acidosis, chronic renal disease, cardiac irritability and arrhythmia, and pregnancy-related toxemia. Medications that can decrease levels include diuretics, insulin, and some antibiotics (Pagana 2021).

Low magnesium may also be associated with kidney stones (Wu 2020), metabolic syndrome (Rodríguez-Moran 2018), diabetes, insulin resistance (Fiorentini 2021), pancreatic exocrine insufficiency (Lindkvist 2012), depression, sleep disturbance (Micke 2021), headaches (Karim 2021), migraines (Samaie 2012), cognitive impairment (Sitzia 2020), a diet high in processed foods and low in leafy greens and whole grains, CVD, vascular calcification, endothelial dysfunction, poor glycemic control, oxidative stress, increased hip fracture risk, increased Alzheimer’s risk, gastrointestinal disorders, refeeding syndrome, sepsis, prolonged exercise, proton pump inhibitors, and epidermal growth factor inhibitors. Very low magnesium can be associated with tetany, seizures, psychosis, and nystagmus (Van Laecke 2019). Inflammation and oxidative stress associated with type 2 DM is associated with low magnesium as well (Verma 2017).

High magnesium levels can be associated magnesium-containing antacids, uncontrolled diabetes, hypothyroidism, renal insufficiency/decreased excretion, slower cardiac conduction, and Addison’s disease. Medications that can increase magnesium include antacids, laxatives, lithium, loop diuretics, thyroid medication, and aminoglycoside antibiotics (Pagana 2021). Very high levels may be associated with tachycardia, hypotension, muscle weakness, and cardiac arrest (Van Laecke 2019). Excess hemolysis can also increase serum magnesium due to its release from red blood cells (Cascella 2022). 


Magnesium is an essential mineral with numerous functions throughout the body most organ function depends on magnesium. It is the second most abundant intracellular element after potassium, assisting in the maintenance of a neutral electrical charge within the cell (Pagana 2021). Magnesium is also required to activate alkaline phosphatase which can be decreased when magnesium is insufficient (Ray 2017).

Magnesium and calcium compete for absorption and transport, and they may counter each other metabolically. They also share the same feedback mechanism so an excess of one can contribute to a deficiency of the other (Dai 2007).

Magnesium’s effects in the body are far-reaching as it functions as a cofactor for more than 600 enzymes and has antioxidant, anti-inflammatory, and anti-apoptotic properties. At the metabolic level it participates in protein and DNA synthesis, oxidative phosphorylation, glycolysis, glycemic control, and signal transduction. Most magnesium is found in the bone and soft tissue and only 1-2% is found extracellularly. Therefore, a magnesium deficiency at the cellular level may be present even with normal serum magnesium. Metabolic complications are associated with a U-shaped curve for serum magnesium with consequences occurring at high and low levels (Van Laecke 2019).

Subclinical magnesium deficiency is common in the general population and signs may be as subtle as fatigue, weakness, and loss of appetite, with symptoms worsening as deficiency progresses. Food sources of magnesium including nuts, seeds, legumes, cocoa, and whole grains. However, food processing, poor soil, and use of high concentrations of potassium and ammonium in fertilizer deplete magnesium (Fiorentini 2021). Insufficient intake is associated with hypertension, CVD, type 2 diabetes, osteoporosis, and neurological complications, reflecting a likely chronic latent magnesium deficit. A serum magnesium below 2.0 mg/dL (0.82 mmol/L) coupled with a urinary magnesium of 40-80 mg/L, indicates insufficient intake of less than 250 mg/day. Insufficiency should be addressed accordingly as the body may compensate for lower serum magnesium by releasing magnesium from the bone (Costello 2016).

Physical symptoms of magnesium insufficiency may also include headache, muscle cramps, depression, sleep disturbances, hypertension, cardiac arrhythmias, electrolyte disorders such as hypocalcemia and hypokalemia, and deficiency of active vitamin D. Researchers note that assessment of magnesium status should include symptoms as well as serum levels, especially if below 2.1 mg/dL (0.85 mmol/L) (Micke 2021).

Low serum magnesium is associated with metabolic syndrome and its individual components, parameters that improve with magnesium supplementation. One 16-week randomized double-blind placebo-controlled study of 198 individuals with metabolic syndrome and low serum magnesium found that provision of 382 mg of elemental magnesium resulted in a significant decrease in systolic and diastolic blood pressure, fasting plasma glucose, and triglyceride levels. Serum magnesium significantly increased from a mean basal level of 1.5 mg/dL (0.62 mmol/L) to 1.9 mg/dL (0.78 mmol/L) versus a slight increase to 1.6 mg/dL (0.66 mmol/L) in the placebo group (Rodríguez-Moran 2018).

Meta-analysis of 1,694 subjects in total revealed that magnesium supplementation improves metabolic parameters in type 2 diabetes as well. Supplementation with 300-400 mg of magnesium per day significantly improved fasting plasma glucose, LDL and HDL cholesterol, triglycerides, and blood pressure in subjects with type 2 diabetes (Verma 2017).

Hypermagnesemia can be seen with markedly elevated levels of 4-6 mg/dL (1.74-2.61 mmol/L) or above and symptoms include hypotension, nausea, vomiting, hyporeflexia, skeletal muscle paralysis, bradyarrhythmia, and even cardiac arrest. Hypermagnesemia is not common and most likely associated with excessive intake or renal insufficiency. In addition to renal compromise, magnesium excretion will decrease in magnesium deficiency when challenged with a magnesium load as the body attempts to retain what it needs (Musso 2009).

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Micke, Oliver et al. “Serum magnesium: time for a standardized and evidence-based reference range.” Magnesium research vol. 34,2 (2021): 84-89. doi:10.1684/mrh.2021.0486

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Rodríguez-Morán, Martha et al. “Oral Magnesium Supplementation and Metabolic Syndrome: A Randomized Double-Blind Placebo-Controlled Clinical Trial.” Advances in chronic kidney disease vol. 25,3 (2018): 261-266. doi:10.1053/j.ackd.2018.02.011

Samaie, Afshin et al. “Blood Magnesium levels in migraineurs within and between the headache attacks: a case control study.” The Pan African medical journal vol. 11 (2012): 46.

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Wu, Jing et al. “Association Between Serum Magnesium and the Prevalence of Kidney Stones: a Cross-sectional Study.” Biological trace element research vol. 195,1 (2020): 20-26. doi:10.1007/s12011-019-01830-3

Tag(s): Biomarkers

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