Magnesium, RBC

PREP: No special fasting required, but the functional medicine community recommends not taking magnesium supplements the morning of the test for consistency. RBC magnesium is the preferred test — serum magnesium reflects less than 1% of body stores and can be 'normal' even with significant deficiency. The functional medicine community targets mid-range or higher on RBC magnesium. Symptoms of deficiency (cramps, poor sleep, anxiety, palpitations, migraines) frequently persist even with normal serum levels. If your provider only orders serum magnesium, request RBC magnesium instead. These notes reflect common practices in thyroid/functional medicine communities.

Reflects common practices in thyroid, BHRT, and functional medicine communities. This may differ from standard clinical guidelines. Not medical advice — always discuss with your provider.