Magnesium: what to pair and what to space apart

Magnesium pairs well with Vitamin D (magnesium is required to activate it), Vitamin B6 (improves cellular uptake), and zinc at modest doses. Separate magnesium from high-dose calcium (over 500 mg) and high-dose zinc (over 25 mg) by at least two hours, all three compete for the same intestinal transporters. Magnesium can reduce the absorption of tetracycline and fluoroquinolone antibiotics, bisphosphonates, and levothyroxine, space these medications by at least 2 to 4 hours. People on diuretics, proton pump inhibitors, or metformin often run low on magnesium and may need higher supplemental doses. Magnesium can lower blood pressure additively with antihypertensives, monitor if you are on multiple cardiovascular medications. Avoid combining with potassium-sparing diuretics without lab monitoring.

The biggest magnesium mistake is choosing the wrong form for the goal, taking magnesium oxide for sleep wastes most of the dose (only 4 percent absorbs), and taking magnesium citrate for anxiety often causes loose stools instead. Another common error is reading the total compound weight on the label rather than elemental magnesium content, a 1,000 mg capsule of magnesium glycinate typically delivers only 100 to 140 mg of elemental magnesium, meaning many people are dramatically under-dosing. People also routinely stack magnesium with calcium and zinc in the same pill, where they compete for absorption. A third pitfall is giving up after a week, magnesium repletion takes 3 to 6 weeks of consistent daily dosing for benefits to appear. Finally, alcohol the same evening can wipe out the calming effect by accelerating urinary magnesium loss overnight.

When something has to be spaced apart, two slots are almost always enough. Put one group with your first meal and the other with your evening meal, roughly 8 to 12 hours apart, which comfortably clears the 2-hour intervals absorption conflicts require. Magnesium goes in the evening slot, and anything it competes with goes in the other. Trying to run three or four slots is where routines break down, most people can hold two.

Absorption conflicts are dose-dependent, not absolute. Trace amounts in food, a splash of milk in coffee or the calcium in a slice of bread, are not the same as a 500mg supplement, and are not worth restructuring your day around. The interactions worth respecting are between two supplements at supplemental doses taken in the same swallow. If you are only taking Magnesium and nothing else, spacing is a non-issue, keep it in a fixed slot and move on.

• Magnesium Glycinate and Calcium
• Magnesium Glycinate and Melatonin
• Magnesium Glycinate and Vitamin D3
• Magnesium Glycinate and Iron
• Magnesium Glycinate and Magnolia Bark
• Magnesium Glycinate and Potassium

• Calcium
• Iron
• Zinc (high doses)

• Can I take magnesium with calcium?+

  Yes, but separate the doses by at least 2 hours if both exceed 250 mg. They share intestinal transporters and compete at high doses. A common evening stack is calcium with dinner and magnesium glycinate 2 hours later, before bed. Low-dose multivitamins that contain both at modest amounts (under 200 mg each) do not require separation.
• Can I take Magnesium in the same handful as everything else?+

  Not quite. Magnesium has documented conflicts with Calcium and Iron, which is what the spacing table above is for. Everything else can go in the same slot.
• Is spacing measured from swallowing or from digestion?+

  From swallowing. The intervals in the table are conventional practical margins that allow the first dose to clear the absorption window in the upper small intestine before the second arrives. There is no need to be precise to the minute, being roughly two hours apart is the point.

• Abbasi B, et al. J Res Med Sci. 2012