Can I take magnesium every day?
Last updated September 3, 2026.
Usually yes - a daily magnesium supplement is safe for most healthy adults within the NIH's 350 mg ceiling for supplemental magnesium; the first sign of excess is diarrhea, with nausea and cramping. Daily needs run about 400 to 420 mg for men and 310 to 320 mg for women from all sources, and many diets fall short. The ceiling exists because extremely high intakes can trigger irregular heartbeat. Two groups need a clinician first: people with kidney disease (the excess cannot be excreted) and anyone on medicines magnesium binds - thyroid tablets, some antibiotics, bisphosphonates all need spacing. Food sources carry no ceiling; the 350 mg line is for pills. Pymander is a free AI doctor, 24/7 by text, and can help you check your specific mix.
What to do
- Stay at or under 350 mg from supplements: food magnesium does not count.
- Diarrhea after starting? That is the signal: lower the dose or split it.
- Kidney disease? Clinician first: excretion is the bottleneck.
- Space it from thyroid pills and certain antibiotics: binding blocks absorption.
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