Major mineral · 300+ enzymes
A cofactor in more than 300 enzyme systems, including energy production, protein building, and muscle and nerve function.
ATP must be bound to magnesium to be active. Also helps muscles relax after contraction and stabilizes heart rhythm.
Bones (about 60%), muscle, every cell's mitochondria.
Pumpkin seeds, almonds, spinach, black beans, whole grains, dark chocolate, bananas.
RDA: 400–420 mg (men), 310–320 mg (women). Upper limit: 350 mg/day from supplements only (no limit for food).
Many people eat less than the RDA; clear deficiency is uncommon and usually linked to illness, alcohol use or medications.
Supplements above the UL commonly cause diarrhea. Dangerous levels mostly occur with kidney failure.
Long-term proton-pump inhibitors can lower magnesium, and magnesium can interfere with absorption of some antibiotics. A pharmacist can advise on timing.
Enzyme roles established. 'Magnesium fixes sleep' and similar claims are not established.
General education only, not medical advice. Drafted Oct 2026 · pending qualified expert review.