MyBody-X angle on Magnesium Check

A 'Magnesium Check' from MyBody-X would likely use a blood or saliva sample to assess magnesium status. However, the clinical utility of such tests is limited: serum magnesium is tightly regulated and does not accurately reflect total body stores; deficiency is often only detectable in red blood cells or muscle tissue. Genetic variants (e.g., in TRPM6) can modestly affect absorption, but the effect sizes are small and not diagnostic. Without symptoms or risk factors (e.g., diabetes, kidney disease), routine testing is not medically recommended. MyBody-X should clearly state that the test is not a substitute for medical diagnosis and that a physician should order appropriate lab work (e.g., ionized magnesium in whole blood) if deficiency is suspected. Evidence: practice-based, not supported by large trials.