New Guidance Sharpens Magnesium Supplement Safety and Use

Overview

• Regulators advise that up to 250 mg per day from supplements without prior testing is generally safe, with diarrhea the most common effect at roughly 250–300 mg.
• The German Nutrition Society sets daily intake targets at 350 mg for men and 300 mg for women, and notes early deficiency signs such as loss of appetite, nausea, fatigue and weakness.
• Higher therapeutic dosing for confirmed deficiency is used under medical supervision—about 243–486 mg per day or divided doses—with lab monitoring because serum values can miss intracellular deficits; whole‑blood targets around 35–37 mg/l are cited.
• Timing is flexible; experts say evening dosing may help with nocturnal issues on plausibility grounds, and athletes may take magnesium directly before or after training.
• People with impaired kidney function or those on interacting medicines should seek medical advice and separate magnesium from iron, zinc or calcium by at least two hours; severe toxicity is rare and typically linked to extreme intakes near or above 2,500 mg per day.