Magnesium (erythrocytes)

This panel measures magnesium inside red blood cells rather than in serum. The distinction matters. Only about 1% of body magnesium is in blood serum, and the body defends that number tightly by pulling magnesium out of bone and tissue, so serum magnesium can look normal while tissue stores are falling. The red cell measurement looks past that regulation.

Magnesium is a cofactor in hundreds of enzyme reactions, including every reaction that uses or produces ATP. It is required for muscle relaxation, nerve signalling, blood glucose regulation and the metabolism of vitamin D.

Below 330 ug/gHb indicates depleted intracellular stores. Commonly reported effects include muscle cramps, eyelid twitching, poor sleep quality, low stress tolerance and constipation.

Losses rise with alcohol intake, chronic stress, heavy sweating and the use of proton pump inhibitors or diuretics. Intake falls when the diet leans on refined grains, since milling removes most of the magnesium in the grain.

Because magnesium is a cofactor for vitamin D metabolism, a low magnesium result can limit how much benefit you get from vitamin D supplementation.

Between 330 and 570 ug/gHb your intracellular magnesium sits inside the reference range for this panel.

Red cell magnesium moves slowly, in line with the roughly 120 day lifespan of the cells being measured, so this is a marker to retest after a season rather than after a fortnight.

Above 570 ug/gHb is uncommon. In people with normal kidney function, excess magnesium from food and ordinary supplement doses is excreted rather than accumulated.

Where it does occur it is usually associated with high-dose supplementation, sometimes from magnesium-containing antacids or laxatives that are not being counted as supplements.

Reduced kidney function is the other route, since magnesium clearance depends on it. A high result is worth reviewing with your practitioner alongside kidney function.

Refined grains lose most of their magnesium during milling, and decades of agricultural intensification have lowered the magnesium content of the soil that food is grown in. Intake has fallen from both directions at once.

Chronic stress accelerates urinary magnesium loss, and alcohol does the same. The Western pattern raises the requirement and lowers the supply at the same time, which is why this marker sits under the Stress Adaptation domain of the Western Lifestyle Index as well as the dietary one.

Pumpkin seeds, almonds, cashews and Brazil nuts are among the densest ordinary sources.

Dark leafy greens supply magnesium at the centre of the chlorophyll molecule. Spinach, chard and kale are the usual candidates.

Legumes, whole grains and dark chocolate contribute meaningfully. Switching from refined to whole grains is one of the larger single changes available.

Magnesium glycinate and magnesium malate are well absorbed and gentle on digestion. Glycinate is the usual choice when sleep or stress is the reason for taking it.

Magnesium citrate absorbs well but has a laxative effect at higher doses, which is sometimes the point and sometimes not.

Magnesium oxide is cheap, poorly absorbed, and largely acts as a laxative. It is the form to avoid if the goal is to raise stores.

Split doses across the day rather than taking one large dose, since absorption falls as the single dose rises.