Your Magnesium Levels Could Skyrocket If You Have This Medical Condition

Magnesium is quite plentiful in the human body, and with good reason. It is a cofactor in over 300 enzyme systems, including protein synthesis, muscle and nerve function, blood sugar control (and here’s what happens to your blood sugar if you don’t get enough magnesium), and blood pressure regulation, just to name a few.

According to the National Institutes of Health Office of Dietary Supplements (ODS), while adults have about 25 grams of magnesium in their bodies, about 50% to 60% of it is stashed away in the bones, with the rest being stored in the body’s soft tissues. Less than 1% is in the blood serum.

Serum magnesium is maintained in a very tight range between 0.75 and 0.95 millimoles per liter (mmol/L). The kidneys bear the main responsibility for this task, causing about 120 milligrams of magnesium to be excreted through the urine on a daily basis. However, if a person has chronic kidney disease (CKD), their magnesium levels could skyrocket.

As the authors of a 2023 narrative review published in Nutrients explain, when the kidney’s glomerular filtration rate falls, it becomes less efficient at filtering the blood. As a result, it cannot excrete magnesium as well as it should, which can lead to too much magnesium remaining in the blood (hypermagnesemia).

According to a 2012 study in the Clinical Kidney Journal, the kidneys can initially compensate and keep magnesium levels normal when CKD is mild to moderate. However, as CKD progresses to stages 4 and 5, serum magnesium begins to rise. Once the patient reaches end-stage renal disease, overt hypermagnesemia becomes common, especially when patients are using medications such as antacids and phosphate binders, which can increase their magnesium intake.

Low blood pressure that doesn’t respond to medication may be the first sign that someone has too much magnesium. In moderate to severe cases, symptoms may also include dizziness, nausea, confusion, weakness, and difficulty breathing. As levels rise even higher, people may experience sleepiness, headache, constipation, muscle or bladder paralysis, abnormal heart rhythms, coma, or even cardiac arrest.

According to experts, in severe cases of magnesium toxicity, it is imperative to obtain timely treatment, including monitoring the person’s ECG, blood pressure, and neuromuscular function (via StatPearls). Treatment may also include intravenous calcium gluconate or chloride to counteract magnesium’s effects on the heart and muscles. Additionally, loop diuretics (or hemodialysis, if the kidneys are too impaired) may be administered to help increase magnesium excretion. During treatment, it is also essential for physicians to monitor the patient’s electrolytes to ensure that they don’t become severely imbalanced, creating even more issues for the patient.