In short, no. “Most people should be concerned about the widespread problem of magnesium inadequacy in our nation, not toxicity,” says Ferira. “With close to half of Americans8 failing to consume baseline magnesium needs each day, I would say let’s aim for a B- before getting scared about an A+ nutritional status.”

But this question was top of mind for me. I eat a pretty magnesium-rich diet and recent bloodwork (of both serum magnesium and red blood cell magnesium) showed I had optimal levels. And while there are nuances when it comes to evaluating magnesium status, I wondered if a sleep-supporting magnesium supplement would still benefit me or if it would be too much. 

“While supplementation regimens vary depending on the functional outcomes of interest (e.g., sleep support, muscle relaxation, cognition, etc.), 100 to 350 mg of magnesium in supplemental form is not only safe for a healthy adult but genuinely useful. Higher levels should be discussed in partnership with a nutrition-minded healthcare practitioner,” asserts Ferira.

And magnesium gets absorbed and used by the body quickly9 (within 12 to 24 hours). So it’s a nutrient that needs to be replenished regularly.