What does a high Magnesium result mean?

A high magnesium level in blood (serum magnesium) is medically uncommon and usually indicates impaired kidney function (e.g., chronic kidney disease), because the kidneys normally excrete excess magnesium. Excessive supplementation (e.g., magnesium pills or antacids) can also raise levels, especially with reduced kidney function. Other causes include dehydration, hypothyroidism, or certain medications (e.g., lithium). A mildly elevated magnesium without symptoms is rarely clinically significant, but levels above 1.1 mmol/L (2.6 mg/dL) define hypermagnesemia; very high levels (>2.0 mmol/L) can cause muscle weakness, low blood pressure, respiratory depression, or cardiac arrhythmias. Important: MyBody-X tests typically measure serum magnesium, not intracellular magnesium, which is more relevant for cellular metabolism. A normal serum level does not rule out intracellular deficiency. If your result is high, consult a doctor to evaluate kidney function (eGFR, creatinine) and rule out other causes. The evidence for reference ranges and clinical consequences is strong (human-strong), but interpretation of a single value without clinical context is limited. Do not self-treat elevated magnesium.